1.14 Adiabatic flow through a valve: S.J.T.0. Joule-Thomson expansion Phase Transformation and Applications Adiabatic:no heat is added or removed from the system. Adiabatic fluid flow through a valve:insulated or the flow is so fast System:valve at steady state H,mn,-H.m。++δW=dU Steady state 8W=0dJ=0 System boundary Adiabatic 89=0 on dim,=6im。 L=H。 Adiabatic process Isenthalpic 绝热过程 SJTU Thermodynamics of Materials Spring 2008 ©X.J.Jin Lecture 2 First Law llPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 2 First Law II 1.14 Adiabatic flow through a valve: Joule-Thomson expansion System: valve at steady state Himi  Homo Q W  dU Adiabatic Q  0 mi  mo Hi  Ho Isenthalpic System boundary mi mo Adiabatic process 绝热过程 Steady state W  0 dU  0 Adiabatic: no heat is added or removed from the system. Adiabatic fluid flow through a valve: insulated or the flow is so fast