上海交通大学：《材料热力学》教学资源_2014课件_lecture 2 First law II

Projection of P-V-T surface of ideal gas S.J.T.U. Phase Transformation and Applications 不同的温度 einssald Volume→ Temperature-> 等温线 等容线 不同的体积 SJTU Thermodynamics of Materials Fall 2012 ©X.J.Jin Lecture 2 First Law ll

Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 2 First Law II Projection of P-V-T surface of ideal gas 等温线 等容线 不同的温度 不同的体积

Internal energy is only a function of temperature S.J.T.U. Phase Transformation and Applications 温度计 Experiment Joule 1843 低压 四+0-0 气体 真空 A B 水浴 Imply... 简单体系（例子：封闭气体）只需由两个变量确定 低压气体的内能仅仅是温度的函数 SJTU Thermodynamics of Materials Fall 2012 ©X.J.Jin Lecture 2 First Law ll

Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 2 First Law II Internal energy is only a function of temperature Experiment Joule 1843 Q W  dU 简单体系（例子：封闭气体）只需由两个变量确定 低压气体的内能仅仅是温度的函数 Imply…

1.15 Equations of State (2) S.J.T.U. Phase Transformation and Applications ldeal gas its internal energy does not change with volume at constant temperature. a H=U+PV av +A恶 +V H =? =0-V+V=0 ap aH =0 av SJTU Thermodynamics of Materials Fall 2012 ©X.J.Jin Lecture 2 First Law ll

Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 2 First Law II 1.15 Equations of State (2) Ideal gas : its internal energy does not change with volume at constant temperature.   0        V T U   ?        P T H V P V P P U P H T T T                            H U  PV V P RT P P V V U P H T T T                                     2   0    0        V V P H T   ?        V T H   0        P T H

1.15 Equations of State (3) S.J.T.U. Phase Transformation and Applications Joule-Thomson coefficient for an ideal gas. aH af 门r= T =0 OH OT)p SJTU Thermodynamics of Materials Fall 2012 ©X.J.Jin Lecture 2 First Law ll

Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 2 First Law II 1.15 Equations of State (3) Joule-Thomson coefficient for an ideal gas.   0        P T H  0                            P T H JT T H P H P T 

1.15 Equations of State (4) S.J.T.U. Phase Transformation and Applications Difference in heat capacities of an ideal gas. c-c-(8 H=U+PY G-q D SJTU Thermodynamics of Materials Fall 2012 ©X.J.Jin Lecture 2 First Law ll

Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 2 First Law II 1.15 Equations of State (4) Difference in heat capacities of an ideal gas. P V P V T U T H C C                    H U  PV P P T P V P T U T H                           P P V P V T U T V P T U C C                            