Contents of Today S.J.T.0. Phase Transformation and Applications Review previous Second law Functions F and G Property relation Property relation derived from U,H,F,and G etc. SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 5 property relation
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 5 property relation Contents of Today Review previous Second law Functions F and G Property relation Property relation derived from U, H, F, and G etc
熵增原理 S.J.T.0. Phase Transformation and Applications 卡诺定理/可用热力学第二定律证明 +s1- 式中Q2为从高温热源吸热 92 T2 Q1为向低温热源放热 1+2≤0 克劳修斯等式（可逆）和不等式( T T2 不可逆过程) 更普遍的循环过程 ≤0 δQ为为系统从温度为T的热源吸取的热量 可逆过程的热温商为零，所定义的熵为状态函数 SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 5 property relation
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 5 property relation 熵增原理 卡诺定理 / 可用热力学第二定律证明 21 1 2 2 QQ T 1 Q T η + = ≤− 式中Q2为从高温热源吸热 Q1为向低温热源放热 1 2 1 2 Q Q 0 T T + ≤ 克劳修斯等式（可逆）和不等式（ 不可逆过程） Q 0 T δ ∫ ≤ 更普遍的循环过程 δQ为为系统从温度为T的热源吸取的热量 可逆过程的热温商为零，所定义的熵为状态函数
熵增原理一热力学第二定律的普遍描述 S.J.T.0. Phase Transformation and Applications δQ为为系统从温度为T的热源吸取的热量 <0 可逆过程的热温商为零，所定义的熵为状态函数 设系统由初态A变为终态B,设系统经过一个 设想的可逆过程由状态B回到状态A 9+≤0 -5.-Sa sas≥归9 热力学第二定律对过程的限制，违反上述不等式的过程是不可能发生的！ SB-SA≥0 绝热条件下 SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 5 property relation
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 5 property relation 熵增原理－热力学第二定律的普遍描述 Q 0 T δ ∫ ≤ δQ为为系统从温度为T的热源吸取的热量 可逆过程的热温商为零，所定义的熵为状态函数 A B 设系统由初态A变为终态B，设系统经过一个 设想的可逆过程由状态B回到状态A B A rev A B Q Q 0 T T δ δ ∫ ∫ + ≤ A rev A B B Q S S T δ ∫ = − B B A A Q S S T δ − ≥ ∫ 热力学第二定律对过程的限制，违反上述不等式的过程是不可能发生的！ SS0 B A − ≥ 绝热条件下
Summary S.J.T.0. Phase Transformation and Applications Some heat must be discarded into a cold sink in order for Hot Source us to generate enough Entropy falls entropy to overcome the Heat withdrawn decline taking place in the hot reservoir Surroundings Energy stored at a high Work temperature has a better Heat dumped quality:high-quality energy Cold sink Entropy is available for doing work; increases low-quality energy,corrupted energy,is less available for doing work冬季取暖/进化 SJTU Thermodynamics of Materials Fall 2012 ©X.J.Jin Lecture 5 property relation
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 5 property relation Some heat must be discarded into a cold sink in order for us to generate enough entropy to overcome the decline taking place in the hot reservoir Energy stored at a high temperature has a better “quality”: high-quality energy is available for doing work; low-quality energy, corrupted energy, is less available for doing work冬季取暖/进化 Summary
热力学第二定律几点说明！ S.J.T.0. Phase Transformation and Applications 过程 研究过程方向问题（任务）《 一不可能的过程 一体系十环境（孤立体系熵增 一可能的过程 原理)《一热力学第二定律( 基础但不好用) ·可逆 ·不可逆（自发）过程 熵为体系的状态函数/平衡状态 B SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 5 property relation
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 5 property relation 热力学第二定律几点说明！ 过程 – 不可能的过程 – 可能的过程 • 可逆 • 不可逆（自发）过程 熵为体系的状态函数/ 平衡状态 研究过程方向问题（任务）《 －体系＋环境（孤立体系熵增 原理）《－热力学第二定律（ 基础但不好用） TI TII A B