热力学系统

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A thermodynamic system is a body of matter and/or radiation, confined in space by walls, with defined permeabilities, which separate it from its surroundings. The surroundings may include other thermodynamic systems, or physical systems that are not thermodynamic systems. A wall of a thermodynamic system may be purely notional, when it is described as being 'permeable' to all matter, all radiation, and all forces.

A thermodynamic system is a body of matter and/or radiation, confined in space by walls, with defined permeabilities, which separate it from its surroundings. The surroundings may include other thermodynamic systems, or physical systems that are not thermodynamic systems. A wall of a thermodynamic system may be purely notional, when it is described as being 'permeable' to all matter, all radiation, and all forces.

热力学系统是一个由物质和/或辐射组成的物体,被墙壁限制在空间中,具有明确的渗透性,将其与周围环境分离开来。环境可能包括其他热力学系统,或不是热力学系统的物理系统。热力学系统的墙可能纯粹是概念上的,当它被描述为对所有物质、所有辐射和所有力量都具有渗透性时。


A widely used distinction is between isolated, closed, and open thermodynamic systems. An isolated thermodynamic system has walls that are non-conductive of heat and perfectly reflective of all radiation, that are rigid and immovable, and that are impermeable to all forms of matter and all forces. (Some writers use the word 'closed' when here the word 'isolated' is being used.)

A widely used distinction is between isolated, closed, and open thermodynamic systems. An isolated thermodynamic system has walls that are non-conductive of heat and perfectly reflective of all radiation, that are rigid and immovable, and that are impermeable to all forms of matter and all forces. (Some writers use the word 'closed' when here the word 'isolated' is being used.)

一个广泛使用的区别是孤立的,封闭的和开放的热力学系统。一个孤立的热力学系统有墙,墙是不导热的,完全反射所有的辐射,是坚硬的和不可移动的,是不可渗透的所有形式的物质和所有的力量。(有些作家在使用“孤立”这个词时会使用“封闭”这个词。)


A closed thermodynamic system is confined by walls that are impermeable to matter, but, by thermodynamic operations, alternately can be made permeable (described as 'diathermal') or impermeable ('adiabatic') to heat, and that, for thermodynamic processes (initiated and terminated by thermodynamic operations), alternately can be allowed or not allowed to move, with system volume change or agitation with internal friction in system contents, as in Joule's original demonstration of the mechanical equivalent of heat, and alternately can be made rough or smooth, so as to allow or not allow heating of the system by friction on its surface.

A closed thermodynamic system is confined by walls that are impermeable to matter, but, by thermodynamic operations, alternately can be made permeable (described as 'diathermal') or impermeable ('adiabatic') to heat, and that, for thermodynamic processes (initiated and terminated by thermodynamic operations), alternately can be allowed or not allowed to move, with system volume change or agitation with internal friction in system contents, as in Joule's original demonstration of the mechanical equivalent of heat, and alternately can be made rough or smooth, so as to allow or not allow heating of the system by friction on its surface.

一个封闭的热力学系统被不透物质的墙所限制,但是,通过热力学运算,可以使其交替渗透(称为‘透热’)或不透热(‘绝热’) ,而对于热力学过程(由热力学运算启动和终止) ,可以允许或不允许其交替运动,通过系统体积的变化或系统内部摩擦的搅动,就像 Joule 对热的机械等效的最初演示,可以使其交替变得粗糙或光滑,以允许或不允许系统表面摩擦加热。


An open thermodynamic system has at least one wall that separates it from another thermodynamic system, which for this purpose is counted as part of the surroundings of the open system, the wall being permeable to at least one chemical substance, as well as to radiation; such a wall, when the open system is in thermodynamic equilibrium, does not sustain a temperature difference across itself.

An open thermodynamic system has at least one wall that separates it from another thermodynamic system, which for this purpose is counted as part of the surroundings of the open system, the wall being permeable to at least one chemical substance, as well as to radiation; such a wall, when the open system is in thermodynamic equilibrium, does not sustain a temperature difference across itself.

一个开放式热力学系统至少有一面墙将其与另一个开放式热力学系统隔开,为此,这面墙被算作开放式系统周围环境的一部分,这面墙可以渗透至少一种化学物质以及辐射; 这样一面墙,当开放式系统在热力学平衡时,不能维持自身的温差。


Furthermore, the state of a thermodynamic system is described by thermodynamic state variables, which may be intensive, such as temperature, or pressure, or extensive, such as entropy, or internal energy.

Furthermore, the state of a thermodynamic system is described by thermodynamic state variables, which may be intensive, such as temperature, or pressure, or extensive, such as entropy, or internal energy.

此外,热力学系统的状态是由热力学状态变量来描述的,这些变量可能是强烈的,比如温度、压力,也可能是广泛的,比如熵,或者内能。


A thermodynamic system is subject to external interventions called thermodynamic operations; these alter the system's walls or its surroundings; as a result, the system undergoes transient thermodynamic processes according to the principles of thermodynamics. Such operations and processes effect changes in the thermodynamic state of the system.

A thermodynamic system is subject to external interventions called thermodynamic operations; these alter the system's walls or its surroundings; as a result, the system undergoes transient thermodynamic processes according to the principles of thermodynamics. Such operations and processes effect changes in the thermodynamic state of the system.

热力学系统受到称为热力学操作的外部干预; 这些改变了系统的墙壁或其周围环境; 因此,系统根据热力学原理经历了瞬态的热力学过程。这样的操作和过程会影响系统热力学状态的变化。


When the intensive state variables of its content vary in space, a thermodynamic system can be considered as many systems contiguous with each other, each being a different thermodynamical system.

When the intensive state variables of its content vary in space, a thermodynamic system can be considered as many systems contiguous with each other, each being a different thermodynamical system.

当其内容的密集状态变量在空间中发生变化时,一个热力学系统可以被认为是许多相邻的系统,每个系统都是一个不同的热力学系统。


A thermodynamic system may comprise several phases, such as ice, liquid water, and water vapour, in mutual thermodynamic equilibrium, mutually unseparated by any wall. Or it may be homogeneous. Such systems may be regarded as 'simple'.

A thermodynamic system may comprise several phases, such as ice, liquid water, and water vapour, in mutual thermodynamic equilibrium, mutually unseparated by any wall. Or it may be homogeneous. Such systems may be regarded as 'simple'.

热力学系统可以由几个相组成,如冰、液态水和水蒸气,在相互作用的热力学平衡中,相互之间没有任何壁分隔。或者它可能是同质的。这样的系统可以被认为是简单的。


A 'compound' thermodynamic system may comprise several simple thermodynamic sub-systems, mutually separated by one or several walls of definite respective permeabilities. It is often convenient to consider such a compound system initially isolated in a state of thermodynamic equilibrium, then affected by a thermodynamic operation of increase of some inter-sub-system wall permeability, to initiate a transient thermodynamic process, so as to generate a final new state of thermodynamic equilibrium. This idea was used, and perhaps introduced, by Carathéodory. In a compound system, initially isolated in a state of thermodynamic equilibrium, a reduction of a wall permeability does not effect a thermodynamic process, nor a change of thermodynamic state. This difference expresses the Second Law of thermodynamics. It illustrates that increase in entropy measures increase in dispersal of energy, due to increase of accessibility of microstates.[1]

A 'compound' thermodynamic system may comprise several simple thermodynamic sub-systems, mutually separated by one or several walls of definite respective permeabilities. It is often convenient to consider such a compound system initially isolated in a state of thermodynamic equilibrium, then affected by a thermodynamic operation of increase of some inter-sub-system wall permeability, to initiate a transient thermodynamic process, so as to generate a final new state of thermodynamic equilibrium. This idea was used, and perhaps introduced, by Carathéodory. In a compound system, initially isolated in a state of thermodynamic equilibrium, a reduction of a wall permeability does not effect a thermodynamic process, nor a change of thermodynamic state. This difference expresses the Second Law of thermodynamics. It illustrates that increase in entropy measures increase in dispersal of energy, due to increase of accessibility of microstates.

一个“化合物”热力学系统可以包括几个简单的热力学子系统,由一个或几个具有确定的各自渗透性的墙相互隔开。考虑这样一个复合体系最初是在热力学平衡状态下孤立的,然后受到某些子体系间壁渗透性增加的热力学操作的影响,启动一个瞬态热力学过程,从而产生一个最终的新热力学平衡状态,通常是比较方便的。这个想法被 Carathéodory 采用了,或许还被引入了。在一个复合体系中,最初孤立于热力学平衡状态,墙体渗透率的降低不会影响热力学过程,也不会影响热力学状态的变化。这种差异反映了热力学第二定律。结果表明,由于微观状态可达性的增加,熵测度的增加导致了能量的分散。


In equilibrium thermodynamics, the state of a thermodynamic system is a state of thermodynamic equilibrium, as opposed to a non-equilibrium state.

In equilibrium thermodynamics, the state of a thermodynamic system is a state of thermodynamic equilibrium, as opposed to a non-equilibrium state.

在平衡态热力学中,热力学系统的状态是热力学平衡的状态,而不是非平衡态。


According to the permeabilities of the walls of a system, transfers of energy and matter occur between it and its surroundings, which are assumed to be unchanging over time, until a state of thermodynamic equilibrium is attained. The only states considered in equilibrium thermodynamics are equilibrium states. Classical thermodynamics includes (a) equilibrium thermodynamics; (b) systems considered in terms of cyclic sequences of processes rather than of states of the system; such were historically important in the conceptual development of the subject. Systems considered in terms of continuously persisting processes described by steady flows are important in engineering.

According to the permeabilities of the walls of a system, transfers of energy and matter occur between it and its surroundings, which are assumed to be unchanging over time, until a state of thermodynamic equilibrium is attained. The only states considered in equilibrium thermodynamics are equilibrium states. Classical thermodynamics includes (a) equilibrium thermodynamics; (b) systems considered in terms of cyclic sequences of processes rather than of states of the system; such were historically important in the conceptual development of the subject. Systems considered in terms of continuously persisting processes described by steady flows are important in engineering.

根据系统墙壁的渗透性,能量和物质在系统与周围环境之间发生转移,这种转移假定随时间不变,直到达到热力学平衡状态。在平衡态热力学中只考虑平衡态。经典热力学包括: (a)平衡态热力学; (b)以循环过程序列而不是系统状态来考虑的系统; 这些在该学科的概念发展中具有历史性的重要性。用稳定流描述的连续持续过程来考虑的系统在工程中是重要的。


The very existence of thermodynamic equilibrium, defining states of thermodynamic systems, is the essential, characteristic, and most fundamental postulate of thermodynamics, though it is only rarely cited as a numbered law.[2][3][4] According to Bailyn, the commonly rehearsed statement of the zeroth law of thermodynamics is a consequence of this fundamental postulate.[5] In reality, practically nothing in nature is in strict thermodynamic equilibrium, but the postulate of thermodynamic equilibrium often provides very useful idealizations or approximations, both theoretically and experimentally; experiments can provide scenarios of practical thermodynamic equilibrium.

The very existence of thermodynamic equilibrium, defining states of thermodynamic systems, is the essential, characteristic, and most fundamental postulate of thermodynamics, though it is only rarely cited as a numbered law. According to Bailyn, the commonly rehearsed statement of the zeroth law of thermodynamics is a consequence of this fundamental postulate. In reality, practically nothing in nature is in strict thermodynamic equilibrium, but the postulate of thermodynamic equilibrium often provides very useful idealizations or approximations, both theoretically and experimentally; experiments can provide scenarios of practical thermodynamic equilibrium.

热力学平衡的存在---- 定义热力学系统的状态---- 是热力学的基本、特征和最基本的假设,尽管它很少被引用为编号定律。根据 Bailyn 的说法,热力学第零定律经常预演的声明就是这个基本假设的结果。事实上,实际上自然界中没有什么是严格的热力学平衡,但热力学平衡的假设常常提供非常有用的理想化或近似,无论是在理论上还是在实验上; 实验可以提供实际热力学平衡的场景。


In equilibrium thermodynamics the state variables do not include fluxes because in a state of thermodynamic equilibrium all fluxes have zero values by definition. Equilibrium thermodynamic processes may involve fluxes but these must have ceased by the time a thermodynamic process or operation is complete bringing a system to its eventual thermodynamic state. Non-equilibrium thermodynamics allows its state variables to include non-zero fluxes, that describe transfers of mass or energy or entropy between a system and its surroundings.[6]

In equilibrium thermodynamics the state variables do not include fluxes because in a state of thermodynamic equilibrium all fluxes have zero values by definition. Equilibrium thermodynamic processes may involve fluxes but these must have ceased by the time a thermodynamic process or operation is complete bringing a system to its eventual thermodynamic state. Non-equilibrium thermodynamics allows its state variables to include non-zero fluxes, that describe transfers of mass or energy or entropy between a system and its surroundings.

在平衡态热力学中,状态变量不包括通量,因为在热力学平衡状态下,所有的通量定义为零。平衡热力学过程可能涉及通量,但这些必须已停止的时候,一个热力学过程或运行完成,使系统的最终热力学状态。非平衡态热力学允许它的状态变量包括非零的流量,这些流量描述了系统与周围环境之间的质量、能量或熵的转移。


In 1824 Sadi Carnot described a thermodynamic system as the working substance (such as the volume of steam) of any heat engine under study.

In 1824 Sadi Carnot described a thermodynamic system as the working substance (such as the volume of steam) of any heat engine under study.

1824年,Sadi Carnot 将热力学系统描述为研究中的任何热机的工作物质(如蒸汽量)。


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拇指


Overview

模板:Thermodynamics


Thermodynamic equilibrium is characterized by absence of flow of mass or energy. Equilibrium thermodynamics, as a subject in physics, considers macroscopic bodies of matter and energy in states of internal thermodynamic equilibrium. It uses the concept of thermodynamic processes, by which bodies pass from one equilibrium state to another by transfer of matter and energy between them. The term 'thermodynamic system' is used to refer to bodies of matter and energy in the special context of thermodynamics. The possible equilibria between bodies are determined by the physical properties of the walls that separate the bodies. Equilibrium thermodynamics in general does not measure time. Equilibrium thermodynamics is a relatively simple and well settled subject. One reason for this is the existence of a well defined physical quantity called 'the entropy of a body'.

Thermodynamic equilibrium is characterized by absence of flow of mass or energy. Equilibrium thermodynamics, as a subject in physics, considers macroscopic bodies of matter and energy in states of internal thermodynamic equilibrium. It uses the concept of thermodynamic processes, by which bodies pass from one equilibrium state to another by transfer of matter and energy between them. The term 'thermodynamic system' is used to refer to bodies of matter and energy in the special context of thermodynamics. The possible equilibria between bodies are determined by the physical properties of the walls that separate the bodies. Equilibrium thermodynamics in general does not measure time. Equilibrium thermodynamics is a relatively simple and well settled subject. One reason for this is the existence of a well defined physical quantity called 'the entropy of a body'.

热力学平衡是拥有属性没有质量或能量的流动。平衡态热力学,作为物理学的一门学科,研究宏观物体的内部热力学平衡和能量。它使用了热力学过程的概念,通过热力学过程,物体通过物质和能量在它们之间的转移,从一个平衡态转移到另一个平衡态。在热力学的特殊背景下,热力学系统一词用来指物质和能量的物体。物体之间可能的平衡是由分隔物体的壁的物理性质决定的。平衡态热力学一般不测量时间。平衡态热力学是一个相对简单而且解决得很好的学科。其中一个原因是存在一个定义明确的物理量,称为物体的熵。


Non-equilibrium thermodynamics, as a subject in physics, considers bodies of matter and energy that are not in states of internal thermodynamic equilibrium, but are usually participating in processes of transfer that are slow enough to allow description in terms of quantities that are closely related to thermodynamic state variables. It is characterized by presence of flows of matter and energy. For this topic, very often the bodies considered have smooth spatial inhomogeneities, so that spatial gradients, for example a temperature gradient, are well enough defined. Thus the description of non-equilibrium thermodynamic systems is a field theory, more complicated than the theory of equilibrium thermodynamics. Non-equilibrium thermodynamics is a growing subject, not an established edifice. In general, it is not possible to find an exactly defined entropy for non-equilibrium problems. For many non-equilibrium thermodynamical problems, an approximately defined quantity called 'time rate of entropy production' is very useful. Non-equilibrium thermodynamics is mostly beyond the scope of the present article.

Non-equilibrium thermodynamics, as a subject in physics, considers bodies of matter and energy that are not in states of internal thermodynamic equilibrium, but are usually participating in processes of transfer that are slow enough to allow description in terms of quantities that are closely related to thermodynamic state variables. It is characterized by presence of flows of matter and energy. For this topic, very often the bodies considered have smooth spatial inhomogeneities, so that spatial gradients, for example a temperature gradient, are well enough defined. Thus the description of non-equilibrium thermodynamic systems is a field theory, more complicated than the theory of equilibrium thermodynamics. Non-equilibrium thermodynamics is a growing subject, not an established edifice. In general, it is not possible to find an exactly defined entropy for non-equilibrium problems. For many non-equilibrium thermodynamical problems, an approximately defined quantity called 'time rate of entropy production' is very useful. Non-equilibrium thermodynamics is mostly beyond the scope of the present article.

非平衡态热力学,作为物理学的一门学科,考虑的是物质和能量的物体不处于内部热力学平衡状态,但是通常参与的转移过程足够慢,以至于可以用与热力学状态变量密切相关的数量来描述。它是物质和能量流动的拥有属性。对于这个主题,通常被考虑的天体具有平滑的空间不均匀性,因此空间梯度,例如温度梯度,是足够明确的。因此,非平衡态热力学系统的描述是场论,比平衡态热力学更复杂。非平衡态热力学是一个正在成长的主题,而不是一座已经建立的大厦。一般来说,不可能为非平衡态问题找到一个准确定义的熵。对于许多非平衡态热力学问题,一个近似定义的量叫做产生熵时间速率是非常有用的。大多数非平衡态热力学超出了本文的范围。


Another kind of thermodynamic system is considered in engineering. It takes part in a flow process. The account is in terms that approximate, well enough in practice in many cases, equilibrium thermodynamical concepts. This is mostly beyond the scope of the present article, and is set out in other articles, for example the article Flow process.

Another kind of thermodynamic system is considered in engineering. It takes part in a flow process. The account is in terms that approximate, well enough in practice in many cases, equilibrium thermodynamical concepts. This is mostly beyond the scope of the present article, and is set out in other articles, for example the article Flow process.

另一种热力学系统被认为是工程学上的。它参与一个流动过程。在许多情况下,这种说法足以近似平衡热力学概念。这大多超出了本文的范围,并在其他文章中进行了阐述,例如文章 Flow process。


History

The first to create the concept of a thermodynamic system was the French physicist Sadi Carnot whose 1824 Reflections on the Motive Power of Fire studied what he called the working substance, e.g., typically a body of water vapor, in steam engines, in regards to the system's ability to do work when heat is applied to it. The working substance could be put in contact with either a heat reservoir (a boiler), a cold reservoir (a stream of cold water), or a piston (to which the working body could do work by pushing on it). In 1850, the German physicist Rudolf Clausius generalized this picture to include the concept of the surroundings, and began referring to the system as a "working body". In his 1850 manuscript On the Motive Power of Fire, Clausius wrote:

The first to create the concept of a thermodynamic system was the French physicist Sadi Carnot whose 1824 Reflections on the Motive Power of Fire studied what he called the working substance, e.g., typically a body of water vapor, in steam engines, in regards to the system's ability to do work when heat is applied to it. The working substance could be put in contact with either a heat reservoir (a boiler), a cold reservoir (a stream of cold water), or a piston (to which the working body could do work by pushing on it). In 1850, the German physicist Rudolf Clausius generalized this picture to include the concept of the surroundings, and began referring to the system as a "working body". In his 1850 manuscript On the Motive Power of Fire, Clausius wrote:

第一个提出热力学系统的概念的是法国物理学家 Sadi Carnot,他在1824年的论火的动力研究了他称之为工作物质的东西,例如,蒸汽机中典型的水蒸气,考虑到系统在加热时做功的能力。工作物质可以与热源(锅炉)、冷源(冷水流)或活塞(工作物体可以通过推动活塞来工作)接触。1850年,德国物理学家鲁道夫 · 克劳修斯(Rudolf Clausius)将这一图景概括为包括周围环境的概念,并开始将这一系统称为“工作体”。在他1850年的手稿《论火的动力》中,克劳修斯写道:


模板:Cquote


The article Carnot heat engine shows the original piston-and-cylinder diagram used by Carnot in discussing his ideal engine; below, we see the Carnot engine as is typically modeled in current use:

The article Carnot heat engine shows the original piston-and-cylinder diagram used by Carnot in discussing his ideal engine; below, we see the Carnot engine as is typically modeled in current use:

文章卡诺热机展示了卡诺在讨论他的理想发动机时使用的原始活塞和气缸图; 下面,我们看到卡诺发动机在当前使用中的典型模型:

文件:Carnot heat engine 2.svg
Carnot engine diagram (modern) – where heat flows from a high temperature TH furnace through the fluid of the "working body" (working substance) and into the cold sink TC, thus forcing the working substance to do mechanical work W on the surroundings, via cycles of contractions and expansions.

Carnot engine diagram (modern) – where heat flows from a high temperature TH furnace through the fluid of the "working body" (working substance) and into the cold sink TC, thus forcing the working substance to do mechanical work W on the surroundings, via cycles of contractions and expansions.

卡诺发动机示意图(现代)——热量从高温 t < sub > h 熔炉通过“工作体”(工作物质)的液体流入冷槽 t < sub > c ,从而迫使工作物质做周围的机械工作 w,通过收缩和扩张循环

In the diagram shown, the "working body" (system), a term introduced by Clausius in 1850, can be any fluid or vapor body through which heat Q can be introduced or transmitted through to produce work. In 1824, Sadi Carnot, in his famous paper Reflections on the Motive Power of Fire, had postulated that the fluid body could be any substance capable of expansion, such as vapor of water, vapor of alcohol, vapor of mercury, a permanent gas, or air, etc. Though, in these early years, engines came in a number of configurations, typically QH was supplied by a boiler, wherein water boiled over a furnace; QC was typically a stream of cold flowing water in the form of a condenser located on a separate part of the engine. The output work W was the movement of the piston as it turned a crank-arm, which typically turned a pulley to lift water out of flooded salt mines. Carnot defined work as "weight lifted through a height".

In the diagram shown, the "working body" (system), a term introduced by Clausius in 1850, can be any fluid or vapor body through which heat Q can be introduced or transmitted through to produce work. In 1824, Sadi Carnot, in his famous paper Reflections on the Motive Power of Fire, had postulated that the fluid body could be any substance capable of expansion, such as vapor of water, vapor of alcohol, vapor of mercury, a permanent gas, or air, etc. Though, in these early years, engines came in a number of configurations, typically QH was supplied by a boiler, wherein water boiled over a furnace; QC was typically a stream of cold flowing water in the form of a condenser located on a separate part of the engine. The output work W was the movement of the piston as it turned a crank-arm, which typically turned a pulley to lift water out of flooded salt mines. Carnot defined work as "weight lifted through a height".

在图表中,“工作体”(系统) ,一个由克劳修斯在1850年引入的术语,可以是任何流体或蒸汽体,通过它们可以引入或传递热 q 以产生功。1824年,Sadi Carnot 在他著名的论文《论火的动力假定液体可以是任何能够膨胀的物质,例如水蒸气、酒精蒸气、水银蒸气、永久性气体或空气等。尽管在早期,发动机有很多种结构,典型的 q < sub > h 由锅炉供应,其中水在炉子上沸腾; q < sub > c 典型的是一股冷水流,以冷凝器的形式,位于发动机的一个单独的部分。输出功 w 是活塞的运动,因为它转动一个曲柄臂,这通常转动一个滑轮举起水淹没的盐矿。卡诺将工作定义为“通过高度提升重量”。


Systems in equilibrium

At thermodynamic equilibrium, a system's properties are, by definition, unchanging in time. Systems in equilibrium are much simpler and easier to understand than systems not in equilibrium. In some cases, when analyzing a thermodynamic process, one can assume that each intermediate state in the process is at equilibrium. This considerably simplifies the analysis.

At thermodynamic equilibrium, a system's properties are, by definition, unchanging in time. Systems in equilibrium are much simpler and easier to understand than systems not in equilibrium. In some cases, when analyzing a thermodynamic process, one can assume that each intermediate state in the process is at equilibrium. This considerably simplifies the analysis.

在热力学平衡,一个系统的属性,根据定义,在时间上是不变的。处于平衡状态的系统比不处于平衡状态的系统更简单,更容易理解。在某些情况下,当分析热力学过程时,我们可以假设过程中的每个居间态都处于平衡状态。这大大简化了分析。


In isolated systems it is consistently observed that as time goes on internal rearrangements diminish and stable conditions are approached. Pressures and temperatures tend to equalize, and matter arranges itself into one or a few relatively homogeneous phases. A system in which all processes of change have gone practically to completion is considered in a state of thermodynamic equilibrium. The thermodynamic properties of a system in equilibrium are unchanging in time. Equilibrium system states are much easier to describe in a deterministic manner than non-equilibrium states.

In isolated systems it is consistently observed that as time goes on internal rearrangements diminish and stable conditions are approached. Pressures and temperatures tend to equalize, and matter arranges itself into one or a few relatively homogeneous phases. A system in which all processes of change have gone practically to completion is considered in a state of thermodynamic equilibrium. The thermodynamic properties of a system in equilibrium are unchanging in time. Equilibrium system states are much easier to describe in a deterministic manner than non-equilibrium states.

在孤立系统中,随着时间的推移,内部重排减少,稳定条件接近。压力和温度趋于均匀,物质自行排列成一个或几个相对均匀的相。如果一个系统中所有的变化过程实际上已经完成,那么这个系统就被认为处于热力学平衡状态。平衡体系的热力学性质在时间上是不变的。平衡态比非平衡态更容易用确定性方法描述。


For a process to be reversible, each step in the process must be reversible. For a step in a process to be reversible, the system must be in equilibrium throughout the step. That ideal cannot be accomplished in practice because no step can be taken without perturbing the system from equilibrium, but the ideal can be approached by making changes slowly.

For a process to be reversible, each step in the process must be reversible. For a step in a process to be reversible, the system must be in equilibrium throughout the step. That ideal cannot be accomplished in practice because no step can be taken without perturbing the system from equilibrium, but the ideal can be approached by making changes slowly.

对于一个过程是可逆的,过程中的每一步都必须是可逆的。为了使过程中的一个步骤是可逆的,系统必须在整个步骤中处于平衡状态。这个理想不可能在实践中实现,因为没有一个步骤可以在不扰乱系统的平衡的情况下采取,但是理想可以通过慢慢地改变来实现。


Walls

{ | class = “ wikitable” align = “ right”
Types of transfers permitted Types of transfers permitted
+ 允许转移的类型
by types of wall by types of wall
+ 按墙的类型排列 type of wall type of wall 墙的类型 type of transfer type of transfer 转移类型
Matter Matter 物质 Work Work 工作 Heat Heat
permeable to matter permeable to matter 无关紧要 Green tickY Red XN Red XN
permeable to energy but permeable to energy but 透过能量,但

impermeable to matter

impermeable to matter

不透物质

Red XN Green tickY Green tickY
adiabatic adiabatic 绝热的 Red XN Green tickY Red XN
adynamic and adynamic and 无名氏和

impermeable to matter

impermeable to matter

不透物质

Red XN Red XN Green tickY
isolating isolating 隔离 Red XN Red XN Red XN

|}

A system is enclosed by walls that bound it and connect it to its surroundings.[7][8][9][10][11][12] Often a wall restricts passage across it by some form of matter or energy, making the connection indirect. Sometimes a wall is no more than an imaginary two-dimensional closed surface through which the connection to the surroundings is direct.

A system is enclosed by walls that bound it and connect it to its surroundings. Often a wall restricts passage across it by some form of matter or energy, making the connection indirect. Sometimes a wall is no more than an imaginary two-dimensional closed surface through which the connection to the surroundings is direct.

一个系统被围墙包围着,围墙把它与周围的环境连接起来。通常一堵墙用某种形式的物质或能量限制穿过它的通道,使得这种联系是间接的。有时候,墙壁只不过是一个虚构的二维封闭表面,通过这个表面,与周围环境的联系是直接的。


A wall can be fixed (e.g. a constant volume reactor) or moveable (e.g. a piston). For example, in a reciprocating engine, a fixed wall means the piston is locked at its position; then, a constant volume process may occur. In that same engine, a piston may be unlocked and allowed to move in and out. Ideally, a wall may be declared adiabatic, diathermal, impermeable, permeable, or semi-permeable. Actual physical materials that provide walls with such idealized properties are not always readily available.

A wall can be fixed (e.g. a constant volume reactor) or moveable (e.g. a piston). For example, in a reciprocating engine, a fixed wall means the piston is locked at its position; then, a constant volume process may occur. In that same engine, a piston may be unlocked and allowed to move in and out. Ideally, a wall may be declared adiabatic, diathermal, impermeable, permeable, or semi-permeable. Actual physical materials that provide walls with such idealized properties are not always readily available.

一堵墙可以固定(例如:。定容反应器)或可移动的(例如:。活塞)。例如,在往复式发动机中,一个固定的壁意味着活塞被锁定在它的位置; 然后,一个恒定的体积过程可能发生。在同一台发动机中,活塞可以解锁并允许进出。理想情况下,墙可以被宣布为绝热、透热、不透水、透水或半透水。为墙体提供这种理想特性的实际物理材料并不总是容易获得。


The system is delimited by walls or boundaries, either actual or notional, across which conserved (such as matter and energy) or unconserved (such as entropy) quantities can pass into and out of the system. The space outside the thermodynamic system is known as the surroundings, a reservoir, or the environment. The properties of the walls determine what transfers can occur. A wall that allows transfer of a quantity is said to be permeable to it, and a thermodynamic system is classified by the permeabilities of its several walls. A transfer between system and surroundings can arise by contact, such as conduction of heat, or by long-range forces such as an electric field in the surroundings.

The system is delimited by walls or boundaries, either actual or notional, across which conserved (such as matter and energy) or unconserved (such as entropy) quantities can pass into and out of the system. The space outside the thermodynamic system is known as the surroundings, a reservoir, or the environment. The properties of the walls determine what transfers can occur. A wall that allows transfer of a quantity is said to be permeable to it, and a thermodynamic system is classified by the permeabilities of its several walls. A transfer between system and surroundings can arise by contact, such as conduction of heat, or by long-range forces such as an electric field in the surroundings.

这个系统是由墙壁或边界所界定的,无论是实际的还是概念上的,守恒量(如物质和能量)或非守恒量(如熵)可以进出这个系统。热力学系统外的空间被称为周围环境、蓄水池或环境。墙壁的特性决定了可以发生什么样的转移。一堵允许一定数量的物质转移的墙被认为是可以渗透的,而一堵热力学系统则是根据其几堵墙的渗透性来分类的。系统和周围环境之间的转移可以通过接触,如热传导,或者通过远程力,如周围环境中的电场来实现。


A system with walls that prevent all transfers is said to be isolated. This is an idealized conception, because in practice some transfer is always possible, for example by gravitational forces. It is an axiom of thermodynamics that an isolated system eventually reaches internal thermodynamic equilibrium, when its state no longer changes with time.

A system with walls that prevent all transfers is said to be isolated. This is an idealized conception, because in practice some transfer is always possible, for example by gravitational forces. It is an axiom of thermodynamics that an isolated system eventually reaches internal thermodynamic equilibrium, when its state no longer changes with time.

一个有防止所有传输的墙的系统被称为是隔离的。这是一个理想化的概念,因为在实践中,某些转移总是可能的,例如重力。一个孤立的系统当它的状态不再随时间改变时,最终达到内部热力学平衡,这是热力学的公理。


The walls of a closed system allow transfer of energy as heat and as work, but not of matter, between it and its surroundings. The walls of an open system allow transfer both of matter and of energy.[13][14][15][16][17][18][19] This scheme of definition of terms is not uniformly used, though it is convenient for some purposes. In particular, some writers use 'closed system' where 'isolated system' is here used.[20][21]

The walls of a closed system allow transfer of energy as heat and as work, but not of matter, between it and its surroundings. The walls of an open system allow transfer both of matter and of energy. This scheme of definition of terms is not uniformly used, though it is convenient for some purposes. In particular, some writers use 'closed system' where 'isolated system' is here used.

封闭系统的墙壁允许能量作为热量和功在它与周围环境之间传递,但不允许物质的传递。开放系统的围墙允许物质和能量的转移。这种术语定义方案虽然在某些用途上很方便,但并未得到统一使用。特别是,有些作者使用“封闭系统” ,这里使用的是“隔离系统”。


Anything that passes across the boundary and effects a change in the contents of the system must be accounted for in an appropriate balance equation. The volume can be the region surrounding a single atom resonating energy, such as Max Planck defined in 1900; it can be a body of steam or air in a steam engine, such as Sadi Carnot defined in 1824. It could also be just one nuclide (i.e. a system of quarks) as hypothesized in quantum thermodynamics.

Anything that passes across the boundary and effects a change in the contents of the system must be accounted for in an appropriate balance equation. The volume can be the region surrounding a single atom resonating energy, such as Max Planck defined in 1900; it can be a body of steam or air in a steam engine, such as Sadi Carnot defined in 1824. It could also be just one nuclide (i.e. a system of quarks) as hypothesized in quantum thermodynamics.

任何通过边界并影响系统内容变化的事情都必须在一个适当的平衡方程中加以考虑。体积可以是一个单原子共振能量周围的区域,如马克斯 · 普朗克在1900年的定义; 它可以是蒸汽机中的蒸汽或空气,如萨迪 · 卡诺在1824年的定义。它也可能只是一个核素(即。量子热力学中假设的夸克系统。


Surroundings

The system is the part of the universe being studied, while the surroundings is the remainder of the universe that lies outside the boundaries of the system. It is also known as the environment, and the reservoir. Depending on the type of system, it may interact with the system by exchanging mass, energy (including heat and work), momentum, electric charge, or other conserved properties. The environment is ignored in analysis of the system, except in regards to these interactions.

The system is the part of the universe being studied, while the surroundings is the remainder of the universe that lies outside the boundaries of the system. It is also known as the environment, and the reservoir. Depending on the type of system, it may interact with the system by exchanging mass, energy (including heat and work), momentum, electric charge, or other conserved properties. The environment is ignored in analysis of the system, except in regards to these interactions.

该系统是被研究的宇宙的一部分,而周围环境是位于该系统边界之外的宇宙的剩余部分。它也被称为环境和水库。根据系统的类型,它可能通过交换质量、能量(包括热和功)、动量、电荷或其他守恒性质与系统相互作用。在系统的分析中,除了这些相互作用外,环境被忽略了。


Closed system

In a closed system, no mass may be transferred in or out of the system boundaries. The system always contains the same amount of matter, but heat and work can be exchanged across the boundary of the system. Whether a system can exchange heat, work, or both is dependent on the property of its boundary.

In a closed system, no mass may be transferred in or out of the system boundaries. The system always contains the same amount of matter, but heat and work can be exchanged across the boundary of the system. Whether a system can exchange heat, work, or both is dependent on the property of its boundary.

在封闭系统中,质量不得进出系统边界。这个系统总是包含相同数量的物质,但是热量和功可以在这个系统的边界上交换。一个系统是否能够交换热量、功或两者都能交换取决于其边界的性质。



One example is fluid being compressed by a piston in a cylinder. Another example of a closed system is a bomb calorimeter, a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction. Electrical energy travels across the boundary to produce a spark between the electrodes and initiates combustion. Heat transfer occurs across the boundary after combustion but no mass transfer takes place either way.

One example is fluid being compressed by a piston in a cylinder. Another example of a closed system is a bomb calorimeter, a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction. Electrical energy travels across the boundary to produce a spark between the electrodes and initiates combustion. Heat transfer occurs across the boundary after combustion but no mass transfer takes place either way.

一个例子是液体被汽缸中的活塞压缩。另一个封闭系统的例子是弹式量热计,一种用于测量特定反应燃烧热的定容量量热计。电能穿过边界在电极之间产生火花并引发燃烧。燃烧后边界处发生了传热,但是两者都没有发生传质。


Beginning with the first law of thermodynamics for an open system, this is expressed as:

Beginning with the first law of thermodynamics for an open system, this is expressed as:

从开放系统的能量守恒定律开始,这表达为:


[math]\displaystyle{ \Delta U=Q-W+m_{i}(h+\frac{1}{2}v^2+gz)_{i}-m_{e}(h+\frac{1}{2}v^2+gz)_{e} }[/math]

[math]\displaystyle{ \Delta U=Q-W+m_{i}(h+\frac{1}{2}v^2+gz)_{i}-m_{e}(h+\frac{1}{2}v^2+gz)_{e} }[/math]

< math > Delta u = Q-W + m { i }(h + frac {1}{2} v ^ 2 + gz) _ { i }-m { e }(h + frac {1}{2} v ^ 2 + gz) _ { e } </math >


where U is internal energy, Q is the heat added to the system, W is the work done by the system, and since no mass is transferred in or out of the system, both expressions involving mass flow are zero and the first law of thermodynamics for a closed system is derived. The first law of thermodynamics for a closed system states that the increase of internal energy of the system equals the amount of heat added to the system minus the work done by the system. For infinitesimal changes the first law for closed systems is stated by:

where U is internal energy, Q is the heat added to the system, W is the work done by the system, and since no mass is transferred in or out of the system, both expressions involving mass flow are zero and the first law of thermodynamics for a closed system is derived. The first law of thermodynamics for a closed system states that the increase of internal energy of the system equals the amount of heat added to the system minus the work done by the system. For infinitesimal changes the first law for closed systems is stated by:

当 u 是内能时,q 是加到系统中的热量,w 是系统所做的功,由于没有质量进出系统,所以两个关于质量流的表达式都是零,并且导出了封闭系统的能量守恒定律。封闭系统的能量守恒定律表示系统内部能量的增加等于加入系统的热量减去系统所做的功。对于无穷小的变化,封闭系统的第一定律是:


[math]\displaystyle{ \mathrm d U= \delta Q -\delta W. }[/math]

[math]\displaystyle{ \mathrm d U= \delta Q -\delta W. }[/math]

数学,数学,数学


If the work is due to a volume expansion by dV at a pressure P then:

If the work is due to a volume expansion by dV at a pressure P then:

如果功是由于体积膨胀,在压强为 p 时,dV 的值,那么:


[math]\displaystyle{ \delta W = P\mathrm d V. }[/math]

[math]\displaystyle{ \delta W = P\mathrm d V. }[/math]

三角洲 w = p mathrm d v


For a homogeneous system undergoing a reversible process, the second law of thermodynamics reads:

For a homogeneous system undergoing a reversible process, the second law of thermodynamics reads:

对于一个正在经历可逆过程的同质系统,美国热力学第二定律协会写道:


[math]\displaystyle{ \delta Q = T \mathrm d S }[/math]

[math]\displaystyle{ \delta Q = T \mathrm d S }[/math]

(数学)三角函数 q = t 数学


where T is the absolute temperature and S is the entropy of the system. With these relations the fundamental thermodynamic relation, used to compute changes in internal energy, is expressed as:

where T is the absolute temperature and S is the entropy of the system. With these relations the fundamental thermodynamic relation, used to compute changes in internal energy, is expressed as:

其中 t 是绝对温度,s 是系统的熵。根据这些关系式,用来计算内能变化的热力学基本关系表示为:


[math]\displaystyle{ \mathrm d U=T\mathrm d S-P\mathrm d V. }[/math]

[math]\displaystyle{ \mathrm d U=T\mathrm d S-P\mathrm d V. }[/math]

数学,数学


For a simple system, with only one type of particle (atom or molecule), a closed system amounts to a constant number of particles. However, for systems undergoing a chemical reaction, there may be all sorts of molecules being generated and destroyed by the reaction process. In this case, the fact that the system is closed is expressed by stating that the total number of each elemental atom is conserved, no matter what kind of molecule it may be a part of. Mathematically:

For a simple system, with only one type of particle (atom or molecule), a closed system amounts to a constant number of particles. However, for systems undergoing a chemical reaction, there may be all sorts of molecules being generated and destroyed by the reaction process. In this case, the fact that the system is closed is expressed by stating that the total number of each elemental atom is conserved, no matter what kind of molecule it may be a part of. Mathematically:

对于一个简单的系统,只有一种粒子(原子或分子) ,一个封闭的系统相当于一个固定数量的粒子。然而,对于正在进行化学反应的系统,可能有各种各样的分子在反应过程中产生和破坏。在这种情况下,系统是封闭的这一事实是通过声明每个元素原子的总数是守恒的来表示的,不管它可能是哪种分子的一部分。数学上:


[math]\displaystyle{ \sum_{j=1}^m a_{ij}N_j=b_i^0 }[/math]

[math]\displaystyle{ \sum_{j=1}^m a_{ij}N_j=b_i^0 }[/math]

[数学]和[数学]和[数学]


where Nj is the number of j-type molecules, aij is the number of atoms of element i in molecule j and bi0 is the total number of atoms of element i in the system, which remains constant, since the system is closed. There is one such equation for each element in the system.

where Nj is the number of j-type molecules, aij is the number of atoms of element i in molecule j and bi0 is the total number of atoms of element i in the system, which remains constant, since the system is closed. There is one such equation for each element in the system.

其中 n < sub > j 是 j 型分子的个数,a < sub > ij 是分子 j 中元素 i 的原子个数,b < sub > i < sup > 0 是系统中元素 i 的原子总数,由于系统是封闭的,所以保持不变。系统中的每个元素都有一个这样的方程。


Isolated system

An isolated system is more restrictive than a closed system as it does not interact with its surroundings in any way. Mass and energy remains constant within the system, and no energy or mass transfer takes place across the boundary. As time passes in an isolated system, internal differences in the system tend to even out and pressures and temperatures tend to equalize, as do density differences. A system in which all equalizing processes have gone practically to completion is in a state of thermodynamic equilibrium.

An isolated system is more restrictive than a closed system as it does not interact with its surroundings in any way. Mass and energy remains constant within the system, and no energy or mass transfer takes place across the boundary. As time passes in an isolated system, internal differences in the system tend to even out and pressures and temperatures tend to equalize, as do density differences. A system in which all equalizing processes have gone practically to completion is in a state of thermodynamic equilibrium.

孤立系统比封闭系统限制更多,因为它不以任何方式与周围环境相互作用。质量和能量在系统内保持不变,没有能量或质量传递发生在边界上。随着时间在一个孤立的系统中流逝,系统内部的差异趋于均衡,压力和温度趋于均衡,密度差异也是如此。一个系统中的所有均衡过程实际上已经完成是在一个热力学平衡的状态。


Truly isolated physical systems do not exist in reality (except perhaps for the universe as a whole), because, for example, there is always gravity between a system with mass and masses elsewhere.[22][23][24][25][26] However, real systems may behave nearly as an isolated system for finite (possibly very long) times. The concept of an isolated system can serve as a useful model approximating many real-world situations. It is an acceptable idealization used in constructing mathematical models of certain natural phenomena.

Truly isolated physical systems do not exist in reality (except perhaps for the universe as a whole), because, for example, there is always gravity between a system with mass and masses elsewhere. However, real systems may behave nearly as an isolated system for finite (possibly very long) times. The concept of an isolated system can serve as a useful model approximating many real-world situations. It is an acceptable idealization used in constructing mathematical models of certain natural phenomena.

真正孤立的物理系统在现实中并不存在(也许除了整个宇宙) ,因为,例如,在一个具有质量的系统和其他地方具有质量的系统之间总是存在引力。然而,实际系统在有限(可能很长)时间内几乎可以表现为一个孤立系统。孤立系统的概念可以作为一个有用的模型来模拟许多真实世界的情况。这是一个可以接受的理想化,用于建立某些自然现象的数学模型。


In the attempt to justify the postulate of entropy increase in the second law of thermodynamics, Boltzmann's H-theorem used equations, which assumed that a system (for example, a gas) was isolated. That is all the mechanical degrees of freedom could be specified, treating the walls simply as mirror boundary conditions. This inevitably led to Loschmidt's paradox. However, if the stochastic behavior of the molecules in actual walls is considered, along with the randomizing effect of the ambient, background thermal radiation, Boltzmann's assumption of molecular chaos can be justified.

In the attempt to justify the postulate of entropy increase in the second law of thermodynamics, Boltzmann's H-theorem used equations, which assumed that a system (for example, a gas) was isolated. That is all the mechanical degrees of freedom could be specified, treating the walls simply as mirror boundary conditions. This inevitably led to Loschmidt's paradox. However, if the stochastic behavior of the molecules in actual walls is considered, along with the randomizing effect of the ambient, background thermal radiation, Boltzmann's assumption of molecular chaos can be justified.

在试图证明热力学第二定律熵增的假设时,Boltzmann 的 h 定理使用了方程,假设系统(例如气体)是孤立的。这是所有的机械自由度可以指定,对待墙壁只是镜像边界条件。这不可避免地导致了洛施密特的悖论。然而,如果考虑分子在实际壁面中的随机行为,以及环境、背景热辐射的随机效应,则可以证明玻尔兹曼的分子混沌假设是正确的。


The second law of thermodynamics for isolated systems states that the entropy of an isolated system not in equilibrium tends to increase over time, approaching maximum value at equilibrium. Overall, in an isolated system, the internal energy is constant and the entropy can never decrease. A closed system's entropy can decrease e.g. when heat is extracted from the system.

The second law of thermodynamics for isolated systems states that the entropy of an isolated system not in equilibrium tends to increase over time, approaching maximum value at equilibrium. Overall, in an isolated system, the internal energy is constant and the entropy can never decrease. A closed system's entropy can decrease e.g. when heat is extracted from the system.

孤立系统的熵热力学第二定律表明,孤立系统不处于平衡状态时的熵随着时间的推移趋于增加,接近平衡状态时的最大值。总的来说,在一个孤立的系统中,内能是恒定的,熵永远不会减少。一个封闭系统的熵可以减少。当热量从系统中散发出来。


It is important to note that isolated systems are not equivalent to closed systems. Closed systems cannot exchange matter with the surroundings, but can exchange energy. Isolated systems can exchange neither matter nor energy with their surroundings, and as such are only theoretical and do not exist in reality (except, possibly, the entire universe).

It is important to note that isolated systems are not equivalent to closed systems. Closed systems cannot exchange matter with the surroundings, but can exchange energy. Isolated systems can exchange neither matter nor energy with their surroundings, and as such are only theoretical and do not exist in reality (except, possibly, the entire universe).

必须指出,孤立系统不等同于封闭系统。封闭系统不能与周围环境交换物质,但可以交换能量。孤立的系统不能与其周围的物质或能量进行交换,因此只是理论上的,在现实中不存在(可能除了整个宇宙)。


It is worth noting that 'closed system' is often used in thermodynamics discussions when 'isolated system' would be correct – i.e. there is an assumption that energy does not enter or leave the system.

It is worth noting that 'closed system' is often used in thermodynamics discussions when 'isolated system' would be correct – i.e. there is an assumption that energy does not enter or leave the system.

值得注意的是,在热力学讨论中,当“孤立系统”是正确的时候,经常使用“封闭系统”。有一个假设,能量不会进入或离开系统。


Selective transfer of matter

For a thermodynamic process, the precise physical properties of the walls and surroundings of the system are important, because they determine the possible processes.

For a thermodynamic process, the precise physical properties of the walls and surroundings of the system are important, because they determine the possible processes.

对于热力学过程来说,墙壁和系统周围环境的精确物理特性非常重要,因为它们决定了可能的过程。


An open system has one or several walls that allow transfer of matter. To account for the internal energy of the open system, this requires energy transfer terms in addition to those for heat and work. It also leads to the idea of the chemical potential.

An open system has one or several walls that allow transfer of matter. To account for the internal energy of the open system, this requires energy transfer terms in addition to those for heat and work. It also leads to the idea of the chemical potential.

一个开放系统有一个或几个墙,允许物质转移。为了解释开放系统的内能,这需要除了热和功的能量转移项以外的能量转移项。这也导致了化学势的概念。


A wall selectively permeable only to a pure substance can put the system in diffusive contact with a reservoir of that pure substance in the surroundings. Then a process is possible in which that pure substance is transferred between system and surroundings. Also, across that wall a contact equilibrium with respect to that substance is possible. By suitable thermodynamic operations, the pure substance reservoir can be dealt with as a closed system. Its internal energy and its entropy can be determined as functions of its temperature, pressure, and mole number.

A wall selectively permeable only to a pure substance can put the system in diffusive contact with a reservoir of that pure substance in the surroundings. Then a process is possible in which that pure substance is transferred between system and surroundings. Also, across that wall a contact equilibrium with respect to that substance is possible. By suitable thermodynamic operations, the pure substance reservoir can be dealt with as a closed system. Its internal energy and its entropy can be determined as functions of its temperature, pressure, and mole number.

只对纯物质进行选择性渗透的壁可使系统与周围环境中的纯物质储存器发生扩散接触。然后,纯物质在系统和环境之间转移的过程是可能的。另外,穿过这堵墙,与该物质的接触平衡是可能的。通过适当的热力学操作,可将纯物质库作为一个封闭系统处理。它的内能和熵可以由它的温度、压力和摩尔数决定。


A thermodynamic operation can render impermeable to matter all system walls other than the contact equilibrium wall for that substance. This allows the definition of an intensive state variable, with respect to a reference state of the surroundings, for that substance. The intensive variable is called the chemical potential; for component substance i it is usually denoted μi. The corresponding extensive variable can be the number of moles Ni of the component substance in the system.

A thermodynamic operation can render impermeable to matter all system walls other than the contact equilibrium wall for that substance. This allows the definition of an intensive state variable, with respect to a reference state of the surroundings, for that substance. The intensive variable is called the chemical potential; for component substance it is usually denoted . The corresponding extensive variable can be the number of moles of the component substance in the system.

一个热力学操作可以使不渗透物质的所有系统墙壁除了接触平衡墙的物质。这允许定义一个密集状态变量,相对于周围物质的参考状态。强度变量叫做化学势,对于组分物质,它通常被称为化学势。相应的扩展变量可以是系统中组分物质的摩尔数。


For a contact equilibrium across a wall permeable to a substance, the chemical potentials of the substance must be same on either side of the wall. This is part of the nature of thermodynamic equilibrium, and may be regarded as related to the zeroth law of thermodynamics.[27]

For a contact equilibrium across a wall permeable to a substance, the chemical potentials of the substance must be same on either side of the wall. This is part of the nature of thermodynamic equilibrium, and may be regarded as related to the zeroth law of thermodynamics.

对于透过物质的壁的接触平衡,该物质的化学势必须在壁的两侧相同。这是热力学平衡的一部分,也可以被认为与热力学第零定律有关。


Open system

模板:Expand section

In an open system, there is an exchange of energy and matter between the system and the surroundings. The presence of reactants in an open beaker is an example of an open system. Here the boundary is an imaginary surface enclosing the beaker and reactants. It is named closed, if borders are impenetrable for substance, but allow transit of energy in the form of heat, and isolated, if there is no exchange of heat and substances. The open system cannot exist in the equilibrium state. To describe deviation of the thermodynamic system from equilibrium, in addition to constitutive variables that was described above, a set of internal variables [math]\displaystyle{ \xi_1, \xi_2,\ldots }[/math] that are called internal variables have been introduced. The equilibrium state is considered to be stable. and the main property of the internal variables, as measures of non-equilibrium of the system, is their trending to disappear; the local law of disappearing can be written as relaxation equation for each internal variable

In an open system, there is an exchange of energy and matter between the system and the surroundings. The presence of reactants in an open beaker is an example of an open system. Here the boundary is an imaginary surface enclosing the beaker and reactants. It is named closed, if borders are impenetrable for substance, but allow transit of energy in the form of heat, and isolated, if there is no exchange of heat and substances. The open system cannot exist in the equilibrium state. To describe deviation of the thermodynamic system from equilibrium, in addition to constitutive variables that was described above, a set of internal variables [math]\displaystyle{ \xi_1, \xi_2,\ldots }[/math] that are called internal variables have been introduced. The equilibrium state is considered to be stable. and the main property of the internal variables, as measures of non-equilibrium of the system, is their trending to disappear; the local law of disappearing can be written as relaxation equation for each internal variable

在开放系统中,系统和周围环境之间存在能量和物质的交换。反应物在开放烧杯中的存在是开放系统的一个例子。在这里,边界是一个假想的表面,包围着烧杯和反应物。如果物质的边界是无法穿透的,那么它就被称为封闭的,但是如果没有热量和物质的交换,它就可以以热量的形式进行能量的转移,并且是孤立的。开放系统不能在平衡状态下存在。为了描述热力学系统偏离平衡的程度,除了上面描述的本构变量外,还引入了一组内部变量,称为内部变量。平衡态被认为是稳定的。内变量作为系统非平衡度量的主要性质是它们趋于消失,消失的局部规律可以写成每个内变量的松弛方程

[math]\displaystyle{ {{NumBlk|:|\lt math\gt {{ NumBlk | : | \lt math \gt \frac{d\xi_i}{dt} = - \frac{1}{\tau_i} \, \left(\xi_i - \xi_i^{(0)} \right),\quad i =1,\,2,\ldots , \frac{d\xi_i}{dt} = - \frac{1}{\tau_i} \, \left(\xi_i - \xi_i^{(0)} \right),\quad i =1,\,2,\ldots , 1} ,左(xi-xi-xi _ i ^ {(0)}右) ,quad i = 1,,2,ldots, }[/math]

 

 

 

 

(1)

</math>|}}

[/math > | }

where [math]\displaystyle{ \tau_i= \tau_i(T, x_1, x_2, \ldots, x_n) }[/math] is a relaxation time of a corresponding variables. It is convenient to consider the initial value [math]\displaystyle{ \xi_i^0 }[/math] are equal to zero.

where [math]\displaystyle{ \tau_i= \tau_i(T, x_1, x_2, \ldots, x_n) }[/math] is a relaxation time of a corresponding variables. It is convenient to consider the initial value [math]\displaystyle{ \xi_i^0 }[/math] are equal to zero.

其中 < math > tau _ i = tau _ i (t,x _ 1,x _ 2,ldots,x _ n) </math > 是对应变量的松弛时间。考虑初始值 < math > xi _ i ^ 0 </math > 等于零是很方便的。


The essential contribution to the thermodynamics of open non-equilibrium systems was made by Ilya Prigogine, when he and his collaborators investigated systems of chemically reacting substances. The stationary states of such systems exists due to exchange of both particles and energy with the environment. In section 8 of the third chapter of his book,[28] Prigogine has specified three contributions to the variation of entropy of the considered open system at the given volume and constant temperature [math]\displaystyle{ T }[/math] . The increment of entropy [math]\displaystyle{ S }[/math] can be calculated according to the formula

The essential contribution to the thermodynamics of open non-equilibrium systems was made by Ilya Prigogine, when he and his collaborators investigated systems of chemically reacting substances. The stationary states of such systems exists due to exchange of both particles and energy with the environment. In section 8 of the third chapter of his book, Prigogine has specified three contributions to the variation of entropy of the considered open system at the given volume and constant temperature [math]\displaystyle{ T }[/math] . The increment of entropy [math]\displaystyle{ S }[/math] can be calculated according to the formula

开放的非平衡系统热力学的本质贡献是由伊利亚普里戈金,当他和他的合作者研究化学反应物质系统。由于粒子和能量与环境的交换,这类系统的静止态是存在的。在他的书的第三章第8节中,Prigogine 详细说明了在给定的体积和恒定的温度下,开放系统熵的变化有三个贡献。根据该公式可以计算出熵的增量 s </math >

[math]\displaystyle{ {{NumBlk|:|\lt math\gt {{ NumBlk | : | \lt math \gt T\,dS = \Delta Q - \sum_{j} \, \Xi_{j} \,\Delta \xi_j + \sum_{\alpha =1}^k\, \mu_\alpha \, \Delta N_\alpha. T\,dS = \Delta Q - \sum_{j} \, \Xi_{j} \,\Delta \xi_j + \sum_{\alpha =1}^k\, \mu_\alpha \, \Delta N_\alpha. T,dS = Delta q-sum { j } ,Xi { j } ,Delta Xi _ j + sum _ { alpha = 1} ^ k,mu _ alpha,Delta n _ alpha. }[/math]

 

 

 

 

(1)

</math>|}}

[/math > | }

The first term on the right hand side of the equation presents a stream of thermal energy into the system; the last term—a stream of energy into the system coming with the stream of particles of substances [math]\displaystyle{ \Delta N_\alpha }[/math] that can be positive or negative, [math]\displaystyle{ \mu_\alpha }[/math] is chemical potential of substance [math]\displaystyle{ \alpha }[/math]. The middle term in (1) depicts energy dissipation (entropy production) due to the relaxation of internal variables [math]\displaystyle{ \xi_j }[/math]. In the case of chemically reacting substances, which was investigated by Prigogine, the internal variables appear to be measures of incompleteness of chemical reactions, that is measures of how much the considered system with chemical reactions is out of equilibrium. The theory can be generalized,[29][30] to consider any deviation from the equilibrium state as an internal variable, so that we consider the set of internal variables [math]\displaystyle{ \xi_j }[/math] in equation (1) to consist of the quantities defining not only degrees of completeness of all chemical reactions occurring in the system, but also the structure of the system, gradients of temperature, difference of concentrations of substances and so on.

The first term on the right hand side of the equation presents a stream of thermal energy into the system; the last term—a stream of energy into the system coming with the stream of particles of substances [math]\displaystyle{ \Delta N_\alpha }[/math] that can be positive or negative, [math]\displaystyle{ \mu_\alpha }[/math] is chemical potential of substance [math]\displaystyle{ \alpha }[/math]. The middle term in (1) depicts energy dissipation (entropy production) due to the relaxation of internal variables [math]\displaystyle{ \xi_j }[/math]. In the case of chemically reacting substances, which was investigated by Prigogine, the internal variables appear to be measures of incompleteness of chemical reactions, that is measures of how much the considered system with chemical reactions is out of equilibrium. The theory can be generalized, to consider any deviation from the equilibrium state as an internal variable, so that we consider the set of internal variables [math]\displaystyle{ \xi_j }[/math] in equation (1) to consist of the quantities defining not only degrees of completeness of all chemical reactions occurring in the system, but also the structure of the system, gradients of temperature, difference of concentrations of substances and so on.

方程式右边的第一项代表了进入系统的热能流; 最后一项ーー进入系统的能量流,伴随着粒子流进入系统,粒子流可以是正的也可以是负的。第一部分的中期描述了由于内部变量的松弛而引起的能量耗散(产生熵)。在化学反应物质的情况下,由普利戈金研究,内部变量似乎是测量不完全的化学反应,也就是测量多少考虑的体系与化学反应是不平衡的。该理论可以推广,将任何偏离平衡态的情况视为一个内变量,因此我们认为方程(1)中的一组内变量不仅包含了体系中发生的所有化学反应的完全程度,而且包含了体系的结构、温度梯度、物质浓度差等。


The Prigogine approach to the open system allow describing the growth and development of living objects in thermodynamic terms.

The Prigogine approach to the open system allow describing the growth and development of living objects in thermodynamic terms.

开放系统的 Prigogine 方法允许用热力学术语描述生命体的生长和发展。


Adiabatic system

An adiabatic system is the one which doesn't allow any heat to be transferred into or out of the system. The [math]\displaystyle{ PV^\gamma = constant }[/math] equation is only valid for an adiabatic system which is also undergoing a reversible process provided it is a closed system having an ideal gas. If it fails to satisfy any of these conditions then only [math]\displaystyle{ dQ=0 }[/math] is true and it cannot be represented in an equation like [math]\displaystyle{ PV^\gamma = constant }[/math] .

An adiabatic system is the one which doesn't allow any heat to be transferred into or out of the system. The [math]\displaystyle{ PV^\gamma = constant }[/math] equation is only valid for an adiabatic system which is also undergoing a reversible process provided it is a closed system having an ideal gas. If it fails to satisfy any of these conditions then only [math]\displaystyle{ dQ=0 }[/math] is true and it cannot be represented in an equation like [math]\displaystyle{ PV^\gamma = constant }[/math] .

绝热系统就是不允许任何热量,进出系统的系统。这个方程只适用于绝热系统,而且绝热系统也在经历可逆过程,前提是它是一个有理想气体的封闭系统。如果它不能满足这些条件中的任何一个,那么只有 < math > dQ = 0 </math > 是正确的,它不能用 < math > PV ^ gamma = constant </math > 这样的方程来表示。


See also


References

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  2. Bailyn, M. (1994). A Survey of Thermodynamics, American Institute of Physics Press, New York, , p. 20.
  3. Tisza, L. (1966). Generalized Thermodynamics, M.I.T Press, Cambridge MA, p. 119.
  4. Marsland, R. III, Brown, H.R., Valente, G. (2015). Time and irreversibility in axiomatic thermodynamics, Am. J. Phys., 83(7): 628–634.
  5. Bailyn, M. (1994). A Survey of Thermodynamics, American Institute of Physics Press, New York, , p. 22.
  6. Eu, B.C. (2002). Generalized Thermodynamics. The Thermodynamics of Irreversible Processes and Generalized Hydrodynamics, Kluwer Academic Publishers, Dordrecht, .
  7. Born, M. (1949). Natural Philosophy of Cause and Chance, Oxford University Press, London, p.44
  8. Tisza, L. (1966), pp. 109, 112.
  9. Haase, R. (1971), p. 7.
  10. Adkins, C.J. (1968/1975), p. 4
  11. Callen, H.B. (1960/1985), pp. 15, 17.
  12. Tschoegl, N.W. (2000), p. 5.
  13. Prigogine, I., Defay, R. (1950/1954). Chemical Thermodynamics, Longmans, Green & Co, London, p. 66.
  14. Tisza, L. (1966). Generalized Thermodynamics, M.I.T Press, Cambridge MA, pp. 112–113.
  15. Guggenheim, E.A. (1949/1967). Thermodynamics. An Advanced Treatment for Chemists and Physicists, (1st edition 1949) 5th edition 1967, North-Holland, Amsterdam, p. 14.
  16. Münster, A. (1970). Classical Thermodynamics, translated by E.S. Halberstadt, Wiley–Interscience, London, pp. 6–7.
  17. Haase, R. (1971). Survey of Fundamental Laws, chapter 1 of Thermodynamics, pages 1–97 of volume 1, ed. W. Jost, of Physical Chemistry. An Advanced Treatise, ed. H. Eyring, D. Henderson, W. Jost, Academic Press, New York, lcn 73–117081, p. 3.
  18. Tschoegl, N.W. (2000). Fundamentals of Equilibrium and Steady-State Thermodynamics, Elsevier, Amsterdam, , p. 5.
  19. Silbey, R.J., Alberty, R.A., Bawendi, M.G. (1955/2005). Physical Chemistry, fourth edition, Wiley, Hoboken NJ, p. 4.
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  21. ter Haar, D., Wergeland, H. (1966). Elements of Thermodynamics, Addison-Wesley Publishing, Reading MA, p. 43.
  22. I.M.Kolesnikov; V.A.Vinokurov; S.I.Kolesnikov (2001). Thermodynamics of Spontaneous and Non-Spontaneous Processes. Nova science Publishers. p. 136. ISBN 978-1-56072-904-4. https://books.google.com/books?id=2RzE2pCfijYC&pg=PA136. 
  23. "A System and Its Surroundings". ChemWiki. University of California - Davis. Retrieved 9 May 2012.
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  26. Material and Energy Balances for Engineers and Environmentalists. Imperial College Press. p. 7. Archived from the original on 15 August 2009. https://web.archive.org/web/20090815150041/http://www.icpress.co.uk/etextbook/p631/p631_chap01.pdf. Retrieved 9 May 2012. 
  27. Bailyn, M. (1994). A Survey of Thermodynamics, American Institute of Physics Press, New York, , pp. 19–23.
  28. Prigogine, I. (1955/1961/1967). Introduction to Thermodynamics of Irreversible Processes. 3rd edition, Wiley Interscience, New York.
  29. Pokrovskii V.N. (2005) Extended thermodynamics in a discrete-system approach, Eur. J. Phys. vol. 26, 769–781.
  30. Pokrovskii V.N. (2013) A derivation of the main relations of non-equilibrium thermodynamics. Hindawi Publishing Corporation: ISRN Thermodynamics, vol. 2013, article ID 906136, 9 p. https://dx.doi.org/10.1155/2013/906136.


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  • Moran, Michael J.; Shapiro, Howard N. (2008). Fundamentals of Engineering Thermodynamics (6th ed.). Wiley. 


模板:Thermodynamic cycles

Category:Thermodynamic systems

类别: 热力学系统

Category:Equilibrium chemistry

类别: 平衡化学

Category:Thermodynamic cycles

类别: 热力循环

Category:Thermodynamic processes

类别: 热力学过程


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