Review S.J.T.0. Phase Transformation and Applications o Entropy state function The second law is concerned with limits on the conversion of“heat"into“work”by heat engines. Through a consideration of an idealized heat engine operating between two heat reservoirs. Carnot found that not all the heat removed from a high temperature reservoir is converted into work. Entropy increase for an isolated system SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 4 Second law ll
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 4 Second law II Review • Entropy / state function • The second law is concerned with limits on the conversion of “heat” into “work” by heat engines. • Through a consideration of an idealized heat engine operating between two heat reservoirs, Carnot found that not all the heat removed from a high temperature reservoir is converted into work. • Entropy increase for an isolated system
热机：航空发动机 S.J.T.0. Phase Transformation and Applications SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 4 Second law ll
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 4 Second law II 热机：航空发动机
抽象 S.J.T.0. Phase Transformation and Applications Energy as work V Carnot engine: Quasistatically,reversible 低温热源为什么要存在？ SJTU Thermodynamics of Materials Fall 2012 @X.J.Jin Lecture 4 Second law ll
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 4 Second law II 抽象 Carnot engine: Quasistatically, reversible 低温热源为什么要存在？
热机 S.J.T.0. Phase Transformation and Applications A D D B B We need a way to reduce the pressure of the gas inside the cylinder,so that during the compression stage less work has to be done to drive the piston back in.adiabatically The essential step in the carnot cycle is to break the thermal contact with the hot reservoir before the piston is fully withdrawn,at B SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 4 Second law ll
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 4 Second law II 热机 We need a way to reduce the pressure of the gas inside the cylinder, so that during the compression stage less work has to be done to drive the piston back in. adiabatically The essential step in the carnot cycle is to break the thermal contact with the hot reservoir before the piston is fully withdrawn, at B
热机2 S.J.T.0. Phase Transformation and Applications Pressure Isothermal expansion Carot cycle Isothermal compression OB Volume Pressure Atkins cycle OA Only reversible isothermal process C Volume SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 4 Second law ll
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 4 Second law II 热机2 Atkins cycle Only reversible isothermal process Carot cycle