“熵增原理”的版本间的差异

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(Moved page from wikipedia:en:Clausius theorem (history))
 
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The Clausius theorem (1855) states that for a thermodynamic system (e.g. heat engine or heat pump) exchanging heat with external reservoirs and undergoing a thermodynamic cycle,
 
The Clausius theorem (1855) states that for a thermodynamic system (e.g. heat engine or heat pump) exchanging heat with external reservoirs and undergoing a thermodynamic cycle,
  
1855年的《美国克劳修斯定理法典》中规定,对于热力学系统来说。热机或热泵)与外部储热器交换热量,并经历一个热力学循环,
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'''克劳修斯定理Clausius theorem'''(1855)指出,对于'''<font color="#ff8000"> 热力学系统Thermodynamic system </font>'''(例如,热机或热泵),当其与'''<font color="#ff8000"> 外部热库External reservoirs</font>'''进行热交换并经历'''<font color="#ff8000"> 热力学循环Thermodynamic cycle</font>'''时,
 
 
 
 
 
 
  
  
 
:<math>\oint \frac{\delta Q}{T_{\text{surr}}} \leq 0,</math>
 
:<math>\oint \frac{\delta Q}{T_{\text{surr}}} \leq 0,</math>
 
<math>\oint \frac{\delta Q}{T_{\text{surr}}} \leq 0,</math>
 
 
0,</math > oint frac { delta q }{ t _ { text { surr }} leq 0,</math >
 
 
 
 
  
  
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where <math>\delta Q</math> is the infinitesimal amount of heat absorbed by the system from the reservoir and <math>T_{\text{surr}}</math> is the temperature of the external reservoir (surroundings) at a particular instant in time. The closed integral is carried out along a thermodynamic process path from the initial/final state to the same initial/final state. In principle, the closed integral can start and end at an arbitrary point along the path.
 
where <math>\delta Q</math> is the infinitesimal amount of heat absorbed by the system from the reservoir and <math>T_{\text{surr}}</math> is the temperature of the external reservoir (surroundings) at a particular instant in time. The closed integral is carried out along a thermodynamic process path from the initial/final state to the same initial/final state. In principle, the closed integral can start and end at an arbitrary point along the path.
  
其中“ math” > delta q </math > 是系统从蓄水池吸收的无穷小的热量,而“ math” > t _ { text { surr } </math > 是外部蓄水池(周围环境)在某一特定时刻的温度。封闭积分是沿着一条热力学过程路径进行的,从初始/终止状态到相同的初始/终止状态。原则上,闭积分可以在路径上的任意点开始和结束。
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其中<math>\delta Q</math>是系统从热库吸收的热量极小值,<math>T_{\text{surr}}</math>是特定时间点外部热库(周围环境)的温度。该表达式是指沿着从初始/最终状态到相同的初始/最终状态的'''<font color="#ff8000"> 热力学过程路径Thermodynamic process path</font>'''执行闭合积分。原则上,该闭合积分可以沿路径的任意点开始和结束。
 
 
  
  
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If there are multiple reservoirs with different temperatures <math>\left(T_1,T_2, \cdots T_n\right)</math>, then Clausius inequality reads:
 
If there are multiple reservoirs with different temperatures <math>\left(T_1,T_2, \cdots T_n\right)</math>, then Clausius inequality reads:
  
如果存在多个温度不同的储层,左(t1,t2,cdots t _ n 右) </math > ,那么克劳修斯不等式如下:
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如果存在有多个具有不同温度<math>\left(T_1,T_2, \cdots T_n\right)</math>的热库,则克劳修斯不等式为:
 
 
  
  
 
:<math>\oint \left(\frac{\delta Q_1}{T_1}+\frac{\delta Q_2}{T_2}+\cdots+\frac{\delta Q_n}{T_n}\right) \leq 0.</math>
 
:<math>\oint \left(\frac{\delta Q_1}{T_1}+\frac{\delta Q_2}{T_2}+\cdots+\frac{\delta Q_n}{T_n}\right) \leq 0.</math>
 
<math>\oint \left(\frac{\delta Q_1}{T_1}+\frac{\delta Q_2}{T_2}+\cdots+\frac{\delta Q_n}{T_n}\right) \leq 0.</math>
 
 
左(frac { delta q _ 1}{ t _ 1} + frac { delta q _ 2}{ t _ 2} + cdots + frac { delta q _ n }{ t _ n }右) leq 0. </math >
 
 
  
  
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In the special case of a reversible process, the equality holds. The reversible case is used to introduce the state function known as entropy. This is because in a cyclic process the variation of a state function is zero. In other words, the Clausius statement states that it is impossible to construct a device whose sole effect is the transfer of heat from a cool reservoir to a hot reservoir. Equivalently, heat spontaneously flows from a hot body to a cooler one, not the other way around.  
 
In the special case of a reversible process, the equality holds. The reversible case is used to introduce the state function known as entropy. This is because in a cyclic process the variation of a state function is zero. In other words, the Clausius statement states that it is impossible to construct a device whose sole effect is the transfer of heat from a cool reservoir to a hot reservoir. Equivalently, heat spontaneously flows from a hot body to a cooler one, not the other way around.  
  
在可逆过程的特殊情况下,平等是成立的。可逆情形用来引入状态函数,即熵。这是因为在循环过程中,状态函数的变化为零。换句话说,克劳修斯的声明指出,不可能建造一个装置,其唯一的作用是将热量从冷库转移到热库。相当于,热量自发地从一个热的物体流向一个较冷的物体,而不是相反。
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当在过程可逆的特殊情况下,该等式成立。其可逆过程可用于引入'''<font color="#ff8000"> 熵Entropy </font>''' '''<font color="#ff8000"> 状态函数State function </font>'''。这是因为在循环过程中,状态函数的变化为零。换句话说,'''<font color="#ff8000"> 克劳修斯表述Clausius statement</font>'''指出,不可能构造出一种装置,使其仅仅将热从低温热库传递至高温热库而不引起其他变化。相当于说,热量只能自发地从高温物体流向相对低温的物体,反向则不行。
  
  
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The generalized "inequality of Clausius"  
 
The generalized "inequality of Clausius"  
  
推广的“克劳修斯不等式”
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克劳修斯的广义不等式为:
 
 
  
  
 
:<math>dS_{\text{sys}} \geq \frac{\delta Q}{T_{\text{surr}}} </math>
 
:<math>dS_{\text{sys}} \geq \frac{\delta Q}{T_{\text{surr}}} </math>
 
<math>dS_{\text{sys}} \geq \frac{\delta Q}{T_{\text{surr}}} </math>
 
 
[数学 > dS { text { sys } geq frac { delta q }{ t _ { text { surr }}} </math >
 
 
  
  
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for an infinitesimal change in entropy S applies not only to cyclic processes, but to any process that occurs in a closed system.
 
for an infinitesimal change in entropy S applies not only to cyclic processes, but to any process that occurs in a closed system.
  
熵 s 中的无穷小的变化不仅适用于循环过程,而且适用于发生在封闭系统中的任何过程。
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对于熵趋近于无穷小变化时,S不仅适用于循环过程,而且适用于封闭系统中发生的任何过程。
  
  
  
==History==
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== History 历史 ==
  
  
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The Clausius theorem is a mathematical explanation of the second law of thermodynamics. It was developed by Rudolf Clausius who intended to explain the relationship between the heat flow in a system and the entropy of the system and its surroundings. Clausius developed this in his efforts to explain entropy and define it quantitatively. In more direct terms, the theorem gives us a way to determine if a cyclical process is reversible or irreversible. The Clausius theorem provides a quantitative formula for understanding the second law.
 
The Clausius theorem is a mathematical explanation of the second law of thermodynamics. It was developed by Rudolf Clausius who intended to explain the relationship between the heat flow in a system and the entropy of the system and its surroundings. Clausius developed this in his efforts to explain entropy and define it quantitatively. In more direct terms, the theorem gives us a way to determine if a cyclical process is reversible or irreversible. The Clausius theorem provides a quantitative formula for understanding the second law.
  
克劳修斯定理是对热力学第二定律的一种数学解释。它是由鲁道夫 · 克劳修斯提出的,他试图解释系统中的热流与系统及其周围环境的熵之间的关系。克劳修斯在解释熵和定义熵的过程中发展了这个理论。用更直接的术语来说,这个定理给我们提供了一种方法,来确定一个循环过程是可逆的还是不可逆的。克劳修斯定理提供了一个理解第二定律的定量公式。
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克劳修斯定理是'''<font color="#ff8000"> 热力学第二定律Second law of thermodynamics</font>'''的数学解释。它是由鲁道夫·克劳修斯Rudolf Clausius提出的。他的目的是解释系统中的热量传递与系统及其周围环境熵之间的关系。当初他为了解释并定量熵而逐步发展出了该公式。更直接地讲,该定理为我们提供了一种确定热循环过程是否可逆的方法,为理解第二定律提供了一个定量公式。
  
  
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Clausius was one of the first to work on the idea of entropy and is even responsible for giving it that name. What is now known as the Clausius theorem was first published in 1862 in Clausius' sixth memoir, "On the Application of the Theorem of the Equivalence of Transformations to Interior Work". Clausius sought to show a proportional relationship between entropy and the energy flow by heating (δQ) into a system. In a system, this heat energy can be transformed into work, and work can be transformed into heat through a cyclical process. Clausius writes that "The algebraic sum of all the transformations occurring in a cyclical process can only be less than zero, or, as an extreme case, equal to nothing." In other words, the equation
 
Clausius was one of the first to work on the idea of entropy and is even responsible for giving it that name. What is now known as the Clausius theorem was first published in 1862 in Clausius' sixth memoir, "On the Application of the Theorem of the Equivalence of Transformations to Interior Work". Clausius sought to show a proportional relationship between entropy and the energy flow by heating (δQ) into a system. In a system, this heat energy can be transformed into work, and work can be transformed into heat through a cyclical process. Clausius writes that "The algebraic sum of all the transformations occurring in a cyclical process can only be less than zero, or, as an extreme case, equal to nothing." In other words, the equation
  
克劳修斯是最早研究熵概念的人之一,他甚至给熵起了这个名字。1862年,克劳修斯在他的第六本回忆录《论等效变换定理在室内工作中的应用》中首次出版了现在被称为《克劳修斯定理。克劳修斯试图通过加热(δq)到一个系统来表明熵和能量流之间的比例关系。在一个系统中,热能可以转化为功,功可以通过循环过程转化为热。克劳修斯写道: “在循环过程中发生的所有变换的代数和只能小于零,或者,在极端情况下,等于零。”换句话说,方程式
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克劳修斯是最早研究熵概念的人之一,甚至负责为其命名。关于现阶段“克劳修斯定理”的称呼最初出现在1862年克劳修斯的第六本回忆录《关于转换等价定理在定量物质内做功的应用》中。克劳修斯试图表达熵与通过加热(其热量表示为δ''Q'')进入系统的能量流之间的比例关系。在系统中,这种热能可以转化为功,并且功也可以通过循环过程转化为热。克劳修斯写道:“在一个循环过程中发生的所有转换的代数和只能小于零,或者说在极端情况下等于零。”也就是如下等式:
 
 
  
  
 
:<math>\oint \frac{\delta Q}{T} = 0</math>
 
:<math>\oint \frac{\delta Q}{T} = 0</math>
 
<math>\oint \frac{\delta Q}{T} = 0</math>
 
 
0 </math > oint frac { delta q }{ t } = 0
 
 
  
  
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with 𝛿Q being energy flow into the system due to heating and T being absolute temperature of the body when that energy is absorbed, is found to be true for any process that is cyclical and reversible. Clausius then took this a step further and determined that the following relation must be found true for any cyclical process that is possible, reversible or not. This relation is the "Clausius inequality".
 
with 𝛿Q being energy flow into the system due to heating and T being absolute temperature of the body when that energy is absorbed, is found to be true for any process that is cyclical and reversible. Clausius then took this a step further and determined that the following relation must be found true for any cyclical process that is possible, reversible or not. This relation is the "Clausius inequality".
  
因为 δq 是由于加热而流入系统的能量,t 是体内吸收能量时的绝对温度,对于任何周期性和可逆的过程都是正确的。克劳修斯又进一步确定,对于任何可能的循环过程,无论可逆与否,都必须找到以下关系式。这种关系就是“克劳修斯不等式”。
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其中𝛿''Q''是由于加热而从外界流入系统的能量,T是吸收能量时该主体的绝对温度,该等式对于任何周期性且可逆的过程均成立。之后,克劳修斯进一步扩展并确定,对于任何可能可逆的或不可逆的周期性过程,必须满足以下关系,即“克劳修斯不等式”。。
 
 
  
  
 
:<math>\oint \frac{\delta Q}{T_{surr}} \leq 0</math>
 
:<math>\oint \frac{\delta Q}{T_{surr}} \leq 0</math>
 
<math>\oint \frac{\delta Q}{T_{surr}} \leq 0</math>
 
 
[ math > oint frac { delta q }{ t _ { surr } leq 0 </math >
 
 
  
  
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Now that this is known, there must be a relation developed between the Clausius inequality and entropy. The amount of entropy S added to the system during the cycle is defined as
 
Now that this is known, there must be a relation developed between the Clausius inequality and entropy. The amount of entropy S added to the system during the cycle is defined as
  
既然已经知道了这一点,那么克劳修斯不等式和熵之间一定存在着某种关系。在循环过程中添加到系统中的熵 s 的量被定义为
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于是现在明确了克劳修斯不等式和熵之间的必然联系。而其周期性过程中所增加的熵量S为:
 
 
  
  
 
:<math>\Delta S {{=}} \oint \frac{\delta Q}{T}</math>
 
:<math>\Delta S {{=}} \oint \frac{\delta Q}{T}</math>
 
<math>\Delta S  \oint \frac{\delta Q}{T}</math>
 
 
数学,数学,数学
 
 
  
  
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It has been determined, as stated in the second law of thermodynamics, that the entropy is a state function: It depends only upon the state that the system is in, and not what path the system took to get there. This is in contrast to the amount of energy added as heat (𝛿Q) and as work (𝛿W), which may vary depending on the path. In a cyclic process, therefore, the entropy of the system at the beginning of the cycle must equal the entropy at the end of the cycle, <math>\Delta S=0</math>, regardless of whether the process is reversible or irreversible. In the irreversible case, entropy will be created in the system, and more entropy must be extracted than was added <math>(\Delta S_{surr}>0)</math> in order to return the system to its original state. In the reversible case, no entropy is created and the amount of entropy added is equal to the amount extracted.
 
It has been determined, as stated in the second law of thermodynamics, that the entropy is a state function: It depends only upon the state that the system is in, and not what path the system took to get there. This is in contrast to the amount of energy added as heat (𝛿Q) and as work (𝛿W), which may vary depending on the path. In a cyclic process, therefore, the entropy of the system at the beginning of the cycle must equal the entropy at the end of the cycle, <math>\Delta S=0</math>, regardless of whether the process is reversible or irreversible. In the irreversible case, entropy will be created in the system, and more entropy must be extracted than was added <math>(\Delta S_{surr}>0)</math> in order to return the system to its original state. In the reversible case, no entropy is created and the amount of entropy added is equal to the amount extracted.
  
正如《热力学第二定律所说,熵是一个状态函数: 它只取决于系统所处的状态,而不取决于系统到达那个状态所走的路径。这与作为热(δq)和作为功(δw)加入的能量相反,后者可能随路径而变化。因此,在循环过程中,系统在循环开始时的熵必须等于循环结束时的熵,< math > Delta s = 0 </math > ,不管这个过程是可逆的还是不可逆的。在不可逆的情况下,系统会产生熵,为了使系统恢复到原来的状态,必须提取比加入 math (Delta s { surr } > 0)更多的熵。在可逆的情况下,不会产生熵,熵的增加量等于提取的量。
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如热力学第二定律所述,熵已经确定是一个状态函数:它仅取决于系统所处的状态,而不取决于系统传递热量的过程路径。这与通过加热(𝛿''Q'')和作功(𝛿''W'')增加的能量是不同的,后者随路径的变化而变化。因此,在循环过程中,无论其是可逆还是不可逆的,系统在循环开始时的熵必须等于循环结束时的熵,即<math>\Delta S=0</math>。在不可逆的情况下,系统会产生熵,而且其提取的熵量会大于已添加的熵量<math>(\Delta S_{surr}>0)</math>,这样才能使系统回到其原始状态。而在循环过程可逆的情况下,系统则不会产生熵,其所添加熵的量等于其提取的量。
  
  
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If the amount of energy added by heating can be measured during the process, and the temperature can be measured during the process, the Clausius inequality can be used to determine whether the process is reversible or irreversible by carrying out the integration in the Clausius inequality.
 
If the amount of energy added by heating can be measured during the process, and the temperature can be measured during the process, the Clausius inequality can be used to determine whether the process is reversible or irreversible by carrying out the integration in the Clausius inequality.
  
如果可以测量加热过程中所增加的能量,并且可以测量过程中的温度,则可以用克劳修斯不等式进行克劳修斯不等式的积分,来确定过程是可逆的还是不可逆的。
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循环过程中,如果能测量出因加热而增加的能量和其温度,那么通过对克劳修斯不等式进行积分,就能确定其过程是否可逆。
  
  
  
==Proof==
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== Proof 证据 ==
  
  
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The temperature that enters in the denominator of the integrand in the Clausius inequality is actually the temperature of the external reservoir with which the system exchanges heat. At each instant of the process, the system is in contact with an external reservoir.
 
The temperature that enters in the denominator of the integrand in the Clausius inequality is actually the temperature of the external reservoir with which the system exchanges heat. At each instant of the process, the system is in contact with an external reservoir.
  
在克劳修斯不等式中,进入被积函数分母的温度,实际上是系统与之交换热量的外部热库的温度。在这个过程的每一个瞬间,系统都与外部储存器接触。
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将克劳修斯不等式积分,其被积函数分母中的温度实际上是系统与之交换热量的外部热库的温度。注意热量传递过程的每个瞬间,系统都与外部热库接触。
  
 
   
 
   
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Because of the Second Law of Thermodynamics, in each infinitesimal heat exchange process between the system and the reservoir, the net change in entropy of the "universe", so to say, is <math> dS_{Total}=dS_{Sys} +dS_{Res} \geq 0 </math>.
 
Because of the Second Law of Thermodynamics, in each infinitesimal heat exchange process between the system and the reservoir, the net change in entropy of the "universe", so to say, is <math> dS_{Total}=dS_{Sys} +dS_{Res} \geq 0 </math>.
  
由于热力学第二定律的存在,在系统和蓄热体之间每一个微小的热交换过程中,“宇宙”熵的净变化,也就是说,是。
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根据热力学第二定律,在系统和热库之间,每个无穷小的热交换过程中,其总体系熵的净变化为<math> dS_{Total}=dS_{Sys} +dS_{Res} \geq 0 </math>。
  
  
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When the system takes in heat by an infinitesimal amount <math>\delta Q_{1}</math>(<math>\geq 0</math>), for the net change in entropy <math>dS_{Total_{1}}</math> in this step to be positive, the temperature of the "hot" reservoir <math>T_{Hot}</math> needs to be slightly greater than the temperature of the system at that instant.  
 
When the system takes in heat by an infinitesimal amount <math>\delta Q_{1}</math>(<math>\geq 0</math>), for the net change in entropy <math>dS_{Total_{1}}</math> in this step to be positive, the temperature of the "hot" reservoir <math>T_{Hot}</math> needs to be slightly greater than the temperature of the system at that instant.  
  
当系统以无限小的量吸收热量时(< math > delta q {1} </math > (< math > geq 0 </math >) ,因为在这一步中熵的净变化为正,“热”库 < t { Hot } </math > 需要比系统当时的温度稍高。
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当系统吸收无穷小的热量<math>\delta Q_{1}</math>(<math>\geq 0</math>)时,为了使此过程中的熵<math>dS_{Total_{1}}</math>的净变量为正,“热”库<math>T_{Hot}</math>的温度必须稍大于该时刻的系统温度。
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If the temperature of the system is given by <math>T_{1}</math> at that instant, then <math> dS_{Sys_{1}}=\frac{\delta Q_{1}}{T_{1}}</math>, and <math>T_{Hot}\geq T_{1}</math> forces us to have:
 
If the temperature of the system is given by <math>T_{1}</math> at that instant, then <math> dS_{Sys_{1}}=\frac{\delta Q_{1}}{T_{1}}</math>, and <math>T_{Hot}\geq T_{1}</math> forces us to have:
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If the temperature of the system is given by <math>T_{1}</math> at that instant, then <math> dS_{Sys_{1}}=\frac{\delta Q_{1}}{T_{1}}</math>, and <math>T_{Hot}\geq T_{1}</math> forces us to have:
 
If the temperature of the system is given by <math>T_{1}</math> at that instant, then <math> dS_{Sys_{1}}=\frac{\delta Q_{1}}{T_{1}}</math>, and <math>T_{Hot}\geq T_{1}</math> forces us to have:
  
如果系统的温度是由 < math > t _ {1} </math > 给出的,那么 < math > dS _ { Sys _ 1} = frac { delta q _ {1}{ t _ {1} </math > < math > t _ { Hot } geq _ {1} </math > 强迫我们:
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如果系统温度在该时刻由<math>T_{1}</math>给出,则<math> dS_{Sys_{1}}=\frac{\delta Q_{1}}{T_{1}}</math><math>T_{Hot}\geq T_{1}</math>迫使我们具有:
 
 
  
  
 
:<math> -dS_{Res_{1}} =\frac{\delta Q_{1}}{T_{Hot}}\leq \frac{\delta Q_{1}}{T_{1}} = dS_{Sys_{1}} </math>
 
:<math> -dS_{Res_{1}} =\frac{\delta Q_{1}}{T_{Hot}}\leq \frac{\delta Q_{1}}{T_{1}} = dS_{Sys_{1}} </math>
 
+
<math> -dS_{Res_{1}} =\frac{\delta Q_{1}}{T_{Hot}}\leq \frac{\delta Q_{1}}{T_{1}} = dS_{Sys_{1}} </math>
 
 
 
< math >-dS _ Res _ {1} = frac { delta q _ {1}{ t _ { Hot } leq frac { delta q _ {1}{ t _ {1}} = dS _ { Sys _ {1} </math >
 
 
 
 
 
  
 
This means the magnitude of the entropy "loss" from the reservoir, <math> |dS_{Res_{1}}|=\frac{\delta Q_{1}}{T_{Hot}} </math> is less than the magnitude of the entropy gain <math>dS_{Sys_{1}}</math>(<math>\geq 0</math>) by the system:
 
This means the magnitude of the entropy "loss" from the reservoir, <math> |dS_{Res_{1}}|=\frac{\delta Q_{1}}{T_{Hot}} </math> is less than the magnitude of the entropy gain <math>dS_{Sys_{1}}</math>(<math>\geq 0</math>) by the system:
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This means the magnitude of the entropy "loss" from the reservoir, <math> |dS_{Res_{1}}|=\frac{\delta Q_{1}}{T_{Hot}} </math> is less than the magnitude of the entropy gain <math>dS_{Sys_{1}}</math>(<math>\geq 0</math>) by the system:
 
This means the magnitude of the entropy "loss" from the reservoir, <math> |dS_{Res_{1}}|=\frac{\delta Q_{1}}{T_{Hot}} </math> is less than the magnitude of the entropy gain <math>dS_{Sys_{1}}</math>(<math>\geq 0</math>) by the system:
  
这意味着从水库的熵“损失”的大小,| dS { Res {1} | = frac { delta q {1}{ t { Hot } </math > 小于系统的熵增 < dS { Sys {1} </math > (< math > geq 0 </math >) :
+
这意味着来自热库的熵“损失”的大小,即<math> |dS_{Res_{1}}|=\frac{\delta Q_{1}}{T_{Hot}} </math>小于了系统熵增加的大小<math>dS_{Sys_{1}}</math>(<math>\geq 0</math>)
  
  
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Similarly, when the system at temperature <math>T_{2}</math> expels heat in magnitude <math>-\delta Q_{2}</math> (<math>\delta Q_{2}\leq 0</math>) into a colder reservoir (at temperature <math>T_{Cold}\leq T_{2}</math>) in an infinitesimal step, then again, for the Second Law of Thermodynamics to hold, one would have, in an exactly similar manner:
 
Similarly, when the system at temperature <math>T_{2}</math> expels heat in magnitude <math>-\delta Q_{2}</math> (<math>\delta Q_{2}\leq 0</math>) into a colder reservoir (at temperature <math>T_{Cold}\leq T_{2}</math>) in an infinitesimal step, then again, for the Second Law of Thermodynamics to hold, one would have, in an exactly similar manner:
 
+
类似地,当温度为<math>T_{2}</math>的系统在瞬间发生的过程内将热量<math>-\delta Q_{2}</math> (<math>\delta Q_{2}\leq 0</math>)排入较冷的热库(温度<math>T_{Cold}\leq T_{2}</math>)时,必须以同上完全相似的方式来满足热力学第二定律:
类似地,当系统在温度 < math > t {2} </math > 将热量以数量级 < math >-delta q {2} </math > (< math > delta q {2} leq 0 </math >)排放到一个较冷的水库中(在温度 < math > t { Cold } leq {2} </math >) ,然后再一次,对于热力学第二定律来说,人们会以完全相同的方式:
 
 
 
  
  
 
:<math display="block"> -dS_{Res_{2}}=\frac{\delta Q_{2}}{T_{Cold}}\leq \frac{\delta Q_{2}}{T_{2}}= dS_{Sys_{2}}  </math>
 
:<math display="block"> -dS_{Res_{2}}=\frac{\delta Q_{2}}{T_{Cold}}\leq \frac{\delta Q_{2}}{T_{2}}= dS_{Sys_{2}}  </math>
 
<math display="block"> -dS_{Res_{2}}=\frac{\delta Q_{2}}{T_{Cold}}\leq \frac{\delta Q_{2}}{T_{2}}= dS_{Sys_{2}}  </math>
 
 
< math display = " block" >-dS _ Res _ {2} = frac { delta q _ {2}{ t _ { Cold } leq frac { delta q _ {2}{ t _ {2}} = dS _ { Sys _ {2} </math >
 
 
  
  
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Here, the amount of heat 'absorbed' by the system is given by <math>\delta Q_{2}</math>(<math>\leq 0</math>), signifying that heat is transferring from the system to the reservoir, with <math>dS_{Sys_{2}}\leq 0</math>. The magnitude of the entropy gained by the reservoir, <math> dS_{Res_{2}}=\frac{|\delta Q_{2}|}{T_{cold}}</math> is greater than the magnitude of the entropy loss of the system <math> |dS_{Sys_{2}}|</math>
 
Here, the amount of heat 'absorbed' by the system is given by <math>\delta Q_{2}</math>(<math>\leq 0</math>), signifying that heat is transferring from the system to the reservoir, with <math>dS_{Sys_{2}}\leq 0</math>. The magnitude of the entropy gained by the reservoir, <math> dS_{Res_{2}}=\frac{|\delta Q_{2}|}{T_{cold}}</math> is greater than the magnitude of the entropy loss of the system <math> |dS_{Sys_{2}}|</math>
  
在这里,系统所“吸收”的热量是通过 < math > delta q _ {2} </math > (< math > leq 0 </math >)给出的,表示热量正从系统传递到储存器,而 < math > dS _ Sys _ {2} leq 0 </math > 。水库所获得的熵的大小,大于系统的熵损失的大小
+
这里系统“吸收”的热量由<math>\delta Q_{2}</math>(<math>\leq 0</math>)给出,表示热量从系统传递到热库,且<math>dS_{Sys_{2}}\leq 0</math>。由热库获得的熵大小<math> dS_{Res_{2}}=\frac{|\delta Q_{2}|}{T_{cold}}</math>,大于系统熵损失的大小<math> |dS_{Sys_{2}}|</math>。
  
  
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Since the total change in entropy for the system is 0 in a cyclic process, if one adds all the infinitesimal steps of heat intake and heat expulsion from the reservoir, signified by the previous two equations, with the temperature of the reservoir at each instant given by <math>T_{surr}</math>, one gets,
 
Since the total change in entropy for the system is 0 in a cyclic process, if one adds all the infinitesimal steps of heat intake and heat expulsion from the reservoir, signified by the previous two equations, with the temperature of the reservoir at each instant given by <math>T_{surr}</math>, one gets,
  
由于系统在循环过程中熵的总变化为0,如果加上前面两个方程所表示的储热器吸热和排热的所有无穷小的步骤,再加上每一瞬间储热器的温度,就得到,
+
由于系统在循环过程中熵总量不变,因此,如果将前面两个方程式表示的所有从热库吸收和排放的热,分解成无穷小的阶段再相加,然后在定义出每个时刻给定热库温度<math>T_{surr}</math>,可得出:
 
 
  
  
 
:<math> -\oint dS_{Res}= \oint \frac{\delta Q}{T_{surr}}\leq \oint dS_{Sys}=0 </math>
 
:<math> -\oint dS_{Res}= \oint \frac{\delta Q}{T_{surr}}\leq \oint dS_{Sys}=0 </math>
 
+
<math> -\oint dS_{Res}= \oint \frac{\delta Q}{T_{surr}}\leq \oint dS_{Sys}=0 </math>
 
 
 
[数学]-oint dS { Res } = oint frac { delta q }{ t _ { surr } leq oint dS { Sys } = 0 </math >
 
 
 
 
 
  
 
In particular,
 
In particular,
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In particular,
 
In particular,
  
特别是,
+
尤其是:
 
 
  
  
 
:<math>\oint \frac{\delta Q}{T_{surr}}\leq 0, </math>
 
:<math>\oint \frac{\delta Q}{T_{surr}}\leq 0, </math>
 
<math>\oint \frac{\delta Q}{T_{surr}}\leq 0, </math>
 
 
0,</math > oint frac { delta q }{ t _ { surr } leq 0,</math >
 
 
  
  
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which was to be proven.
 
which was to be proven.
  
这是有待证实的。
+
得到了证明。
  
  
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In summary, (the inequality in the third statement below, being obviously guaranteed by the second law of thermodynamics, which is the basis of our calculation),  
 
In summary, (the inequality in the third statement below, being obviously guaranteed by the second law of thermodynamics, which is the basis of our calculation),  
  
总之,(下面第三个陈述中的不平等,显然得到了我们计算的基础---- 美国热力学第二定律的保证) ,
+
综上所述,我们得出(下面第三条陈述中的不等式显然来自于热力学第二定律,这是我们计算的基础),
 
 
  
  
 
:<math>\oint dS_{Res}\geq 0 </math>
 
:<math>\oint dS_{Res}\geq 0 </math>
 
<math>\oint dS_{Res}\geq 0 </math>
 
 
0 </math > oint dS { Res } geq 0
 
  
 
:<math>\oint dS_{Sys}=0 </math> (as hypothesized)
 
:<math>\oint dS_{Sys}=0 </math> (as hypothesized)
 
<math>\oint dS_{Sys}=0 </math> (as hypothesized)
 
 
[ math > oint dS _ { Sys } = 0
 
  
 
:<math>\oint dS_{Total}=\oint dS_{Res}+\oint dS_{Sys}\geq 0</math>
 
:<math>\oint dS_{Total}=\oint dS_{Res}+\oint dS_{Sys}\geq 0</math>
 
<math>\oint dS_{Total}=\oint dS_{Res}+\oint dS_{Sys}\geq 0</math>
 
 
[数学][数学][数学][数学]
 
 
  
  
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For a reversible cyclic process, there is no generation of entropy in each of the infinitesimal heat transfer processes, so the following equality holds,
 
For a reversible cyclic process, there is no generation of entropy in each of the infinitesimal heat transfer processes, so the following equality holds,
  
对于可逆循环过程,在每一个无限小的传热过程中都不会产生熵,因此下面的等式成立,
+
对于可逆循环过程,在每个无穷小的传热阶段中都不会产生熵,因此以下等式成立:
 
 
  
  
 
:<math>\oint \frac{\delta Q_{rev}}{T}=0. </math>
 
:<math>\oint \frac{\delta Q_{rev}}{T}=0. </math>
 
<math>\oint \frac{\delta Q_{rev}}{T}=0. </math>
 
 
0.0.0.数学
 
 
  
  
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Thus, the Clausius inequality is a consequence of applying the second law of thermodynamics at each infinitesimal stage of heat transfer, and is thus in a sense a weaker condition than the Second Law itself.
 
Thus, the Clausius inequality is a consequence of applying the second law of thermodynamics at each infinitesimal stage of heat transfer, and is thus in a sense a weaker condition than the Second Law itself.
  
因此,克劳修斯不等式是在传热的每一个无穷小阶段应用热力学第二定律的结果,因此在某种意义上比第二定律本身更弱。
+
因此,克劳修斯不等式是基于热力学第二定律并应用在热传递过程中每个无穷小阶段的结果,从某种意义上说,它是热力学第二定律的弱条件。
  
  
  
==See also==
+
== See also 其他参考资料 ==
  
 
* [[Kelvin-Planck statement]]
 
* [[Kelvin-Planck statement]]
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* [[Introduction to entropy]]
 
* [[Introduction to entropy]]
  
 +
 +
* [['''<font color="#ff8000"> 开尔文-普朗克表述Kelvin-Planck statement </font>''']]
 +
* [['''<font color="#ff8000"> 卡诺定理(热力学)Carnot's theorem (thermodynamics </font>''')]]
 +
* [['''<font color="#ff8000"> 卡诺热机Carnot heat engine </font>''']]
 +
* [['''<font color="#ff8000"> 熵的介绍Introduction to entropy </font>''']]
  
  
==References==
+
== References 参考文献 ==
  
 
{{reflist}}
 
{{reflist}}
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==Further reading==
+
== Further reading 拓展阅读==
  
 
*Morton, A. S., and P.J. Beckett. ''Basic Thermodynamics''. New York: Philosophical Library Inc., 1969. Print.
 
*Morton, A. S., and P.J. Beckett. ''Basic Thermodynamics''. New York: Philosophical Library Inc., 1969. Print.
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*Clausius, Rudolf. ''The Mechanical Theory of Heat''. London: Taylor and Francis, 1867. eBook
 
*Clausius, Rudolf. ''The Mechanical Theory of Heat''. London: Taylor and Francis, 1867. eBook
 +
 +
 +
*Morton, A. S., and P.J. Beckett. '' '''<font color="#ff8000"> 热力学基础 Basic Thermodynamics </font>''' ''. New York: Philosophical Library Inc., 1969. Print.
 +
*Saad, Michel A. '' '''<font color="#ff8000"> 工程热力学 Thermodynamics for Engineers </font>''' ''. Englewood Cliffs: Prentice-Hall, 1966. Print.
 +
*Hsieh, Jui Sheng. '' '''<font color="#ff8000"> 热力学原理Principles of Thermodynamics </font>''' ''. Washington, D.C.: Scripta Book Company, 1975. Print.
 +
*Zemansky, Mark W. '' '''<font color="#ff8000"> 热与热力学Heat and Thermodynamics </font>''' ''. 4th ed. New York: McGwaw-Hill Book Company, 1957. Print.
 +
*Clausius, Rudolf. '' '''<font color="#ff8000"> 热力学理论The Mechanical Theory of Heat </font>''' ''. London: Taylor and Francis, 1867. eBook
 +
  
 
{{refend}}
 
{{refend}}
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==External links==
+
== External links 相关链接 ==
  
 
*{{cite web|title=Proof of Clausius's theorem|url=http://theory.ph.man.ac.uk/~judith/stat_therm/node30.html|accessdate=October 4, 2010|author=Judith McGovern|date=2004-03-17|archive-url=https://web.archive.org/web/20110719052220/http://theory.ph.man.ac.uk/~judith/stat_therm/node30.html|archive-date=July 19, 2011|url-status=dead}}
 
*{{cite web|title=Proof of Clausius's theorem|url=http://theory.ph.man.ac.uk/~judith/stat_therm/node30.html|accessdate=October 4, 2010|author=Judith McGovern|date=2004-03-17|archive-url=https://web.archive.org/web/20110719052220/http://theory.ph.man.ac.uk/~judith/stat_therm/node30.html|archive-date=July 19, 2011|url-status=dead}}
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*{{cite book|title=The Mechanical Theory of Heat (eBook)|url=https://books.google.com/books?id=8LIEAAAAYAAJ |accessdate=December 1, 2011}}
 
*{{cite book|title=The Mechanical Theory of Heat (eBook)|url=https://books.google.com/books?id=8LIEAAAAYAAJ |accessdate=December 1, 2011}}
  
 +
 +
Judith McGovern (2004-03-17). " '''<font color="#ff8000"> 克劳修斯定理的证明Proof of Clausius's theorem </font>''' ". Archived from the original on July 19, 2011. Retrieved October 4, 2010.
 +
 +
" '''<font color="#ff8000"> 克劳修斯不等式和热力学第二定律的数学表述The Clausius Inequality And The Mathematical Statement Of The Second Law </font>''' " (PDF). Retrieved October 5, 2010.
 +
 +
'''<font color="#ff8000"> 热力学原理The Mechanical Theory of Heat </font>''' (eBook). Retrieved December 1, 2011.
  
  

2020年12月20日 (日) 22:59的版本

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模板:Thermodynamics


The Clausius theorem (1855) states that for a thermodynamic system (e.g. heat engine or heat pump) exchanging heat with external reservoirs and undergoing a thermodynamic cycle,

The Clausius theorem (1855) states that for a thermodynamic system (e.g. heat engine or heat pump) exchanging heat with external reservoirs and undergoing a thermodynamic cycle,

克劳修斯定理Clausius theorem(1855)指出,对于 热力学系统Thermodynamic system (例如,热机或热泵),当其与 外部热库External reservoirs进行热交换并经历 热力学循环Thermodynamic cycle时,


[math]\displaystyle{ \oint \frac{\delta Q}{T_{\text{surr}}} \leq 0, }[/math]


where [math]\displaystyle{ \delta Q }[/math] is the infinitesimal amount of heat absorbed by the system from the reservoir and [math]\displaystyle{ T_{\text{surr}} }[/math] is the temperature of the external reservoir (surroundings) at a particular instant in time. The closed integral is carried out along a thermodynamic process path from the initial/final state to the same initial/final state. In principle, the closed integral can start and end at an arbitrary point along the path.

where [math]\displaystyle{ \delta Q }[/math] is the infinitesimal amount of heat absorbed by the system from the reservoir and [math]\displaystyle{ T_{\text{surr}} }[/math] is the temperature of the external reservoir (surroundings) at a particular instant in time. The closed integral is carried out along a thermodynamic process path from the initial/final state to the same initial/final state. In principle, the closed integral can start and end at an arbitrary point along the path.

其中[math]\displaystyle{ \delta Q }[/math]是系统从热库吸收的热量极小值,[math]\displaystyle{ T_{\text{surr}} }[/math]是特定时间点外部热库(周围环境)的温度。该表达式是指沿着从初始/最终状态到相同的初始/最终状态的 热力学过程路径Thermodynamic process path执行闭合积分。原则上,该闭合积分可以沿路径的任意点开始和结束。


If there are multiple reservoirs with different temperatures [math]\displaystyle{ \left(T_1,T_2, \cdots T_n\right) }[/math], then Clausius inequality reads:

If there are multiple reservoirs with different temperatures [math]\displaystyle{ \left(T_1,T_2, \cdots T_n\right) }[/math], then Clausius inequality reads:

如果存在有多个具有不同温度[math]\displaystyle{ \left(T_1,T_2, \cdots T_n\right) }[/math]的热库,则克劳修斯不等式为:


[math]\displaystyle{ \oint \left(\frac{\delta Q_1}{T_1}+\frac{\delta Q_2}{T_2}+\cdots+\frac{\delta Q_n}{T_n}\right) \leq 0. }[/math]


In the special case of a reversible process, the equality holds.[1] The reversible case is used to introduce the state function known as entropy. This is because in a cyclic process the variation of a state function is zero. In other words, the Clausius statement states that it is impossible to construct a device whose sole effect is the transfer of heat from a cool reservoir to a hot reservoir.[2] Equivalently, heat spontaneously flows from a hot body to a cooler one, not the other way around.[3]

In the special case of a reversible process, the equality holds. The reversible case is used to introduce the state function known as entropy. This is because in a cyclic process the variation of a state function is zero. In other words, the Clausius statement states that it is impossible to construct a device whose sole effect is the transfer of heat from a cool reservoir to a hot reservoir. Equivalently, heat spontaneously flows from a hot body to a cooler one, not the other way around.

当在过程可逆的特殊情况下,该等式成立。其可逆过程可用于引入 熵Entropy 状态函数State function 。这是因为在循环过程中,状态函数的变化为零。换句话说, 克劳修斯表述Clausius statement指出,不可能构造出一种装置,使其仅仅将热从低温热库传递至高温热库而不引起其他变化。相当于说,热量只能自发地从高温物体流向相对低温的物体,反向则不行。


The generalized "inequality of Clausius"[4]

The generalized "inequality of Clausius"

克劳修斯的广义不等式为:


[math]\displaystyle{ dS_{\text{sys}} \geq \frac{\delta Q}{T_{\text{surr}}} }[/math]


for an infinitesimal change in entropy S applies not only to cyclic processes, but to any process that occurs in a closed system.

for an infinitesimal change in entropy S applies not only to cyclic processes, but to any process that occurs in a closed system.

对于熵趋近于无穷小变化时,S不仅适用于循环过程,而且适用于封闭系统中发生的任何过程。


History 历史

The Clausius theorem is a mathematical explanation of the second law of thermodynamics. It was developed by Rudolf Clausius who intended to explain the relationship between the heat flow in a system and the entropy of the system and its surroundings. Clausius developed this in his efforts to explain entropy and define it quantitatively. In more direct terms, the theorem gives us a way to determine if a cyclical process is reversible or irreversible. The Clausius theorem provides a quantitative formula for understanding the second law.

The Clausius theorem is a mathematical explanation of the second law of thermodynamics. It was developed by Rudolf Clausius who intended to explain the relationship between the heat flow in a system and the entropy of the system and its surroundings. Clausius developed this in his efforts to explain entropy and define it quantitatively. In more direct terms, the theorem gives us a way to determine if a cyclical process is reversible or irreversible. The Clausius theorem provides a quantitative formula for understanding the second law.

克劳修斯定理是 热力学第二定律Second law of thermodynamics的数学解释。它是由鲁道夫·克劳修斯Rudolf Clausius提出的。他的目的是解释系统中的热量传递与系统及其周围环境熵之间的关系。当初他为了解释并定量熵而逐步发展出了该公式。更直接地讲,该定理为我们提供了一种确定热循环过程是否可逆的方法,为理解第二定律提供了一个定量公式。


Clausius was one of the first to work on the idea of entropy and is even responsible for giving it that name. What is now known as the Clausius theorem was first published in 1862 in Clausius' sixth memoir, "On the Application of the Theorem of the Equivalence of Transformations to Interior Work". Clausius sought to show a proportional relationship between entropy and the energy flow by heating (δQ) into a system. In a system, this heat energy can be transformed into work, and work can be transformed into heat through a cyclical process. Clausius writes that "The algebraic sum of all the transformations occurring in a cyclical process can only be less than zero, or, as an extreme case, equal to nothing." In other words, the equation

Clausius was one of the first to work on the idea of entropy and is even responsible for giving it that name. What is now known as the Clausius theorem was first published in 1862 in Clausius' sixth memoir, "On the Application of the Theorem of the Equivalence of Transformations to Interior Work". Clausius sought to show a proportional relationship between entropy and the energy flow by heating (δQ) into a system. In a system, this heat energy can be transformed into work, and work can be transformed into heat through a cyclical process. Clausius writes that "The algebraic sum of all the transformations occurring in a cyclical process can only be less than zero, or, as an extreme case, equal to nothing." In other words, the equation

克劳修斯是最早研究熵概念的人之一,甚至负责为其命名。关于现阶段“克劳修斯定理”的称呼最初出现在1862年克劳修斯的第六本回忆录《关于转换等价定理在定量物质内做功的应用》中。克劳修斯试图表达熵与通过加热(其热量表示为δQ)进入系统的能量流之间的比例关系。在系统中,这种热能可以转化为功,并且功也可以通过循环过程转化为热。克劳修斯写道:“在一个循环过程中发生的所有转换的代数和只能小于零,或者说在极端情况下等于零。”也就是如下等式:


[math]\displaystyle{ \oint \frac{\delta Q}{T} = 0 }[/math]


with 𝛿Q being energy flow into the system due to heating and T being absolute temperature of the body when that energy is absorbed, is found to be true for any process that is cyclical and reversible. Clausius then took this a step further and determined that the following relation must be found true for any cyclical process that is possible, reversible or not. This relation is the "Clausius inequality".

with 𝛿Q being energy flow into the system due to heating and T being absolute temperature of the body when that energy is absorbed, is found to be true for any process that is cyclical and reversible. Clausius then took this a step further and determined that the following relation must be found true for any cyclical process that is possible, reversible or not. This relation is the "Clausius inequality".

其中𝛿Q是由于加热而从外界流入系统的能量,T是吸收能量时该主体的绝对温度,该等式对于任何周期性且可逆的过程均成立。之后,克劳修斯进一步扩展并确定,对于任何可能可逆的或不可逆的周期性过程,必须满足以下关系,即“克劳修斯不等式”。。


[math]\displaystyle{ \oint \frac{\delta Q}{T_{surr}} \leq 0 }[/math]


Now that this is known, there must be a relation developed between the Clausius inequality and entropy. The amount of entropy S added to the system during the cycle is defined as

Now that this is known, there must be a relation developed between the Clausius inequality and entropy. The amount of entropy S added to the system during the cycle is defined as

于是现在明确了克劳修斯不等式和熵之间的必然联系。而其周期性过程中所增加的熵量S为:


[math]\displaystyle{ \Delta S {{=}} \oint \frac{\delta Q}{T} }[/math]


It has been determined, as stated in the second law of thermodynamics, that the entropy is a state function: It depends only upon the state that the system is in, and not what path the system took to get there. This is in contrast to the amount of energy added as heat (𝛿Q) and as work (𝛿W), which may vary depending on the path. In a cyclic process, therefore, the entropy of the system at the beginning of the cycle must equal the entropy at the end of the cycle, [math]\displaystyle{ \Delta S=0 }[/math], regardless of whether the process is reversible or irreversible. In the irreversible case, entropy will be created in the system, and more entropy must be extracted than was added [math]\displaystyle{ (\Delta S_{surr}\gt 0) }[/math] in order to return the system to its original state. In the reversible case, no entropy is created and the amount of entropy added is equal to the amount extracted.

It has been determined, as stated in the second law of thermodynamics, that the entropy is a state function: It depends only upon the state that the system is in, and not what path the system took to get there. This is in contrast to the amount of energy added as heat (𝛿Q) and as work (𝛿W), which may vary depending on the path. In a cyclic process, therefore, the entropy of the system at the beginning of the cycle must equal the entropy at the end of the cycle, [math]\displaystyle{ \Delta S=0 }[/math], regardless of whether the process is reversible or irreversible. In the irreversible case, entropy will be created in the system, and more entropy must be extracted than was added [math]\displaystyle{ (\Delta S_{surr}\gt 0) }[/math] in order to return the system to its original state. In the reversible case, no entropy is created and the amount of entropy added is equal to the amount extracted.

如热力学第二定律所述,熵已经确定是一个状态函数:它仅取决于系统所处的状态,而不取决于系统传递热量的过程路径。这与通过加热(𝛿Q)和作功(𝛿W)增加的能量是不同的,后者随路径的变化而变化。因此,在循环过程中,无论其是可逆还是不可逆的,系统在循环开始时的熵必须等于循环结束时的熵,即[math]\displaystyle{ \Delta S=0 }[/math]。在不可逆的情况下,系统会产生熵,而且其提取的熵量会大于已添加的熵量[math]\displaystyle{ (\Delta S_{surr}\gt 0) }[/math],这样才能使系统回到其原始状态。而在循环过程可逆的情况下,系统则不会产生熵,其所添加熵的量等于其提取的量。


If the amount of energy added by heating can be measured during the process, and the temperature can be measured during the process, the Clausius inequality can be used to determine whether the process is reversible or irreversible by carrying out the integration in the Clausius inequality.

If the amount of energy added by heating can be measured during the process, and the temperature can be measured during the process, the Clausius inequality can be used to determine whether the process is reversible or irreversible by carrying out the integration in the Clausius inequality.

循环过程中,如果能测量出因加热而增加的能量和其温度,那么通过对克劳修斯不等式进行积分,就能确定其过程是否可逆。


Proof 证据

The temperature that enters in the denominator of the integrand in the Clausius inequality is actually the temperature of the external reservoir with which the system exchanges heat. At each instant of the process, the system is in contact with an external reservoir.

The temperature that enters in the denominator of the integrand in the Clausius inequality is actually the temperature of the external reservoir with which the system exchanges heat. At each instant of the process, the system is in contact with an external reservoir.

将克劳修斯不等式积分,其被积函数分母中的温度实际上是系统与之交换热量的外部热库的温度。注意热量传递过程的每个瞬间,系统都与外部热库接触。


Because of the Second Law of Thermodynamics, in each infinitesimal heat exchange process between the system and the reservoir, the net change in entropy of the "universe", so to say, is [math]\displaystyle{ dS_{Total}=dS_{Sys} +dS_{Res} \geq 0 }[/math].

Because of the Second Law of Thermodynamics, in each infinitesimal heat exchange process between the system and the reservoir, the net change in entropy of the "universe", so to say, is [math]\displaystyle{ dS_{Total}=dS_{Sys} +dS_{Res} \geq 0 }[/math].

根据热力学第二定律,在系统和热库之间,每个无穷小的热交换过程中,其总体系熵的净变化为[math]\displaystyle{ dS_{Total}=dS_{Sys} +dS_{Res} \geq 0 }[/math]


When the system takes in heat by an infinitesimal amount [math]\displaystyle{ \delta Q_{1} }[/math]([math]\displaystyle{ \geq 0 }[/math]), for the net change in entropy [math]\displaystyle{ dS_{Total_{1}} }[/math] in this step to be positive, the temperature of the "hot" reservoir [math]\displaystyle{ T_{Hot} }[/math] needs to be slightly greater than the temperature of the system at that instant.

When the system takes in heat by an infinitesimal amount [math]\displaystyle{ \delta Q_{1} }[/math]([math]\displaystyle{ \geq 0 }[/math]), for the net change in entropy [math]\displaystyle{ dS_{Total_{1}} }[/math] in this step to be positive, the temperature of the "hot" reservoir [math]\displaystyle{ T_{Hot} }[/math] needs to be slightly greater than the temperature of the system at that instant.

当系统吸收无穷小的热量[math]\displaystyle{ \delta Q_{1} }[/math]([math]\displaystyle{ \geq 0 }[/math])时,为了使此过程中的熵[math]\displaystyle{ dS_{Total_{1}} }[/math]的净变量为正,“热”库[math]\displaystyle{ T_{Hot} }[/math]的温度必须稍大于该时刻的系统温度。


If the temperature of the system is given by [math]\displaystyle{ T_{1} }[/math] at that instant, then [math]\displaystyle{ dS_{Sys_{1}}=\frac{\delta Q_{1}}{T_{1}} }[/math], and [math]\displaystyle{ T_{Hot}\geq T_{1} }[/math] forces us to have:

If the temperature of the system is given by [math]\displaystyle{ T_{1} }[/math] at that instant, then [math]\displaystyle{ dS_{Sys_{1}}=\frac{\delta Q_{1}}{T_{1}} }[/math], and [math]\displaystyle{ T_{Hot}\geq T_{1} }[/math] forces us to have:

如果系统温度在该时刻由[math]\displaystyle{ T_{1} }[/math]给出,则[math]\displaystyle{ dS_{Sys_{1}}=\frac{\delta Q_{1}}{T_{1}} }[/math][math]\displaystyle{ T_{Hot}\geq T_{1} }[/math]迫使我们具有:


[math]\displaystyle{ -dS_{Res_{1}} =\frac{\delta Q_{1}}{T_{Hot}}\leq \frac{\delta Q_{1}}{T_{1}} = dS_{Sys_{1}} }[/math]


This means the magnitude of the entropy "loss" from the reservoir, [math]\displaystyle{ |dS_{Res_{1}}|=\frac{\delta Q_{1}}{T_{Hot}} }[/math] is less than the magnitude of the entropy gain [math]\displaystyle{ dS_{Sys_{1}} }[/math]([math]\displaystyle{ \geq 0 }[/math]) by the system:

This means the magnitude of the entropy "loss" from the reservoir, [math]\displaystyle{ |dS_{Res_{1}}|=\frac{\delta Q_{1}}{T_{Hot}} }[/math] is less than the magnitude of the entropy gain [math]\displaystyle{ dS_{Sys_{1}} }[/math]([math]\displaystyle{ \geq 0 }[/math]) by the system:

这意味着来自热库的熵“损失”的大小,即[math]\displaystyle{ |dS_{Res_{1}}|=\frac{\delta Q_{1}}{T_{Hot}} }[/math]小于了系统熵增加的大小[math]\displaystyle{ dS_{Sys_{1}} }[/math]([math]\displaystyle{ \geq 0 }[/math]):


Similarly, when the system at temperature [math]\displaystyle{ T_{2} }[/math] expels heat in magnitude [math]\displaystyle{ -\delta Q_{2} }[/math] ([math]\displaystyle{ \delta Q_{2}\leq 0 }[/math]) into a colder reservoir (at temperature [math]\displaystyle{ T_{Cold}\leq T_{2} }[/math]) in an infinitesimal step, then again, for the Second Law of Thermodynamics to hold, one would have, in an exactly similar manner:

Similarly, when the system at temperature [math]\displaystyle{ T_{2} }[/math] expels heat in magnitude [math]\displaystyle{ -\delta Q_{2} }[/math] ([math]\displaystyle{ \delta Q_{2}\leq 0 }[/math]) into a colder reservoir (at temperature [math]\displaystyle{ T_{Cold}\leq T_{2} }[/math]) in an infinitesimal step, then again, for the Second Law of Thermodynamics to hold, one would have, in an exactly similar manner: 类似地,当温度为[math]\displaystyle{ T_{2} }[/math]的系统在瞬间发生的过程内将热量[math]\displaystyle{ -\delta Q_{2} }[/math] ([math]\displaystyle{ \delta Q_{2}\leq 0 }[/math])排入较冷的热库(温度[math]\displaystyle{ T_{Cold}\leq T_{2} }[/math])时,必须以同上完全相似的方式来满足热力学第二定律:


[math]\displaystyle{ -dS_{Res_{2}}=\frac{\delta Q_{2}}{T_{Cold}}\leq \frac{\delta Q_{2}}{T_{2}}= dS_{Sys_{2}} }[/math]


Here, the amount of heat 'absorbed' by the system is given by [math]\displaystyle{ \delta Q_{2} }[/math]([math]\displaystyle{ \leq 0 }[/math]), signifying that heat is transferring from the system to the reservoir, with [math]\displaystyle{ dS_{Sys_{2}}\leq 0 }[/math]. The magnitude of the entropy gained by the reservoir, [math]\displaystyle{ dS_{Res_{2}}=\frac{|\delta Q_{2}|}{T_{cold}} }[/math] is greater than the magnitude of the entropy loss of the system [math]\displaystyle{ |dS_{Sys_{2}}| }[/math]

Here, the amount of heat 'absorbed' by the system is given by [math]\displaystyle{ \delta Q_{2} }[/math]([math]\displaystyle{ \leq 0 }[/math]), signifying that heat is transferring from the system to the reservoir, with [math]\displaystyle{ dS_{Sys_{2}}\leq 0 }[/math]. The magnitude of the entropy gained by the reservoir, [math]\displaystyle{ dS_{Res_{2}}=\frac{|\delta Q_{2}|}{T_{cold}} }[/math] is greater than the magnitude of the entropy loss of the system [math]\displaystyle{ |dS_{Sys_{2}}| }[/math]

这里系统“吸收”的热量由[math]\displaystyle{ \delta Q_{2} }[/math]([math]\displaystyle{ \leq 0 }[/math])给出,表示热量从系统传递到热库,且[math]\displaystyle{ dS_{Sys_{2}}\leq 0 }[/math]。由热库获得的熵大小[math]\displaystyle{ dS_{Res_{2}}=\frac{|\delta Q_{2}|}{T_{cold}} }[/math],大于系统熵损失的大小[math]\displaystyle{ |dS_{Sys_{2}}| }[/math]


Since the total change in entropy for the system is 0 in a cyclic process, if one adds all the infinitesimal steps of heat intake and heat expulsion from the reservoir, signified by the previous two equations, with the temperature of the reservoir at each instant given by [math]\displaystyle{ T_{surr} }[/math], one gets,

Since the total change in entropy for the system is 0 in a cyclic process, if one adds all the infinitesimal steps of heat intake and heat expulsion from the reservoir, signified by the previous two equations, with the temperature of the reservoir at each instant given by [math]\displaystyle{ T_{surr} }[/math], one gets,

由于系统在循环过程中熵总量不变,因此,如果将前面两个方程式表示的所有从热库吸收和排放的热,分解成无穷小的阶段再相加,然后在定义出每个时刻给定热库温度[math]\displaystyle{ T_{surr} }[/math],可得出:


[math]\displaystyle{ -\oint dS_{Res}= \oint \frac{\delta Q}{T_{surr}}\leq \oint dS_{Sys}=0 }[/math]


In particular,

In particular,

尤其是:


[math]\displaystyle{ \oint \frac{\delta Q}{T_{surr}}\leq 0, }[/math]


which was to be proven.

which was to be proven.

得到了证明。


In summary, (the inequality in the third statement below, being obviously guaranteed by the second law of thermodynamics, which is the basis of our calculation),

In summary, (the inequality in the third statement below, being obviously guaranteed by the second law of thermodynamics, which is the basis of our calculation),

综上所述,我们得出(下面第三条陈述中的不等式显然来自于热力学第二定律,这是我们计算的基础),


[math]\displaystyle{ \oint dS_{Res}\geq 0 }[/math]
[math]\displaystyle{ \oint dS_{Sys}=0 }[/math] (as hypothesized)
[math]\displaystyle{ \oint dS_{Total}=\oint dS_{Res}+\oint dS_{Sys}\geq 0 }[/math]


For a reversible cyclic process, there is no generation of entropy in each of the infinitesimal heat transfer processes, so the following equality holds,

For a reversible cyclic process, there is no generation of entropy in each of the infinitesimal heat transfer processes, so the following equality holds,

对于可逆循环过程,在每个无穷小的传热阶段中都不会产生熵,因此以下等式成立:


[math]\displaystyle{ \oint \frac{\delta Q_{rev}}{T}=0. }[/math]


Thus, the Clausius inequality is a consequence of applying the second law of thermodynamics at each infinitesimal stage of heat transfer, and is thus in a sense a weaker condition than the Second Law itself.

Thus, the Clausius inequality is a consequence of applying the second law of thermodynamics at each infinitesimal stage of heat transfer, and is thus in a sense a weaker condition than the Second Law itself.

因此,克劳修斯不等式是基于热力学第二定律并应用在热传递过程中每个无穷小阶段的结果,从某种意义上说,它是热力学第二定律的弱条件。


See also 其他参考资料


  • [[ 开尔文-普朗克表述Kelvin-Planck statement ]]
  • [[ 卡诺定理(热力学)Carnot's theorem (thermodynamics )]]
  • [[ 卡诺热机Carnot heat engine ]]
  • [[ 熵的介绍Introduction to entropy ]]


References 参考文献

  1. Clausius theorem at Wolfram Research
  2. Finn, Colin B. P. Thermal Physics. 2nd ed., CRC Press, 1993.
  3. Giancoli, Douglas C. Physics: Principles with Applications. 6th ed., Pearson/Prentice Hall, 2005.
  4. Mortimer, R. G. Physical Chemistry. 3rd ed., p. 120, Academic Press, 2008.


Further reading 拓展阅读

  • Morton, A. S., and P.J. Beckett. Basic Thermodynamics. New York: Philosophical Library Inc., 1969. Print.
  • Saad, Michel A. Thermodynamics for Engineers. Englewood Cliffs: Prentice-Hall, 1966. Print.
  • Hsieh, Jui Sheng. Principles of Thermodynamics. Washington, D.C.: Scripta Book Company, 1975. Print.
  • Zemansky, Mark W. Heat and Thermodynamics. 4th ed. New York: McGwaw-Hill Book Company, 1957. Print.
  • Clausius, Rudolf. The Mechanical Theory of Heat. London: Taylor and Francis, 1867. eBook


  • Morton, A. S., and P.J. Beckett. 热力学基础 Basic Thermodynamics . New York: Philosophical Library Inc., 1969. Print.
  • Saad, Michel A. 工程热力学 Thermodynamics for Engineers . Englewood Cliffs: Prentice-Hall, 1966. Print.
  • Hsieh, Jui Sheng. 热力学原理Principles of Thermodynamics . Washington, D.C.: Scripta Book Company, 1975. Print.
  • Zemansky, Mark W. 热与热力学Heat and Thermodynamics . 4th ed. New York: McGwaw-Hill Book Company, 1957. Print.
  • Clausius, Rudolf. 热力学理论The Mechanical Theory of Heat . London: Taylor and Francis, 1867. eBook



External links 相关链接

  • Judith McGovern (2004-03-17). "Proof of Clausius's theorem". Archived from the original on July 19, 2011. Retrieved October 4, 2010.


Judith McGovern (2004-03-17). " 克劳修斯定理的证明Proof of Clausius's theorem ". Archived from the original on July 19, 2011. Retrieved October 4, 2010.

" 克劳修斯不等式和热力学第二定律的数学表述The Clausius Inequality And The Mathematical Statement Of The Second Law " (PDF). Retrieved October 5, 2010.

热力学原理The Mechanical Theory of Heat (eBook). Retrieved December 1, 2011.

Category:Laws of thermodynamics

类别: 热力学定律

Category:Physics theorems

范畴: 物理学定理


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