1.17 Adiabatic Compression or Expansion (4) S.J.T.U. Phase Transformation and Applications Helium,ideal gas Valve First gas, Insulated 50-liter,25C,20 atm Quench chamber,?10 atm (H,)m,-(H。)6n。+82+oW=dU=0 System boundary om; dmm。 H=H。 T=T。 H(T,P)=H(T) Quench chamber,?10 atm,Close system Define the system as the quantity 片%-只=0 of gas remaining in the tank when T the pressure reaches 10 atm Adiabatic expansion T=T(0.758)=298×0.758=226K 226K/-47C SJTU Thermodynamics of Materials Spring 2010 ©X.J.Jin Lecture 3 Second law IPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2010 © X. J. Jin Lecture 3 Second law I 1.17 Adiabatic Compression or Expansion (4) Helium, ideal gas Insulated 50-liter, 25 C, 20 atm Quench chamber, ?, 10 atm (Hi )mi (Ho )mo QW  dU  0 Valve Hi  Ho  5 2 0.4 1 2 1 2 ) (0.5) 20 10  ( )  (  R R C R P P P T T T2 T1 (0.758)  2980.758  226 K 226K / -47 C System boundary mi mo First gas, ? Ti  To Quench chamber, ?, 10 atm， Close system H(T,P)  H(T) Define the system as the quantity of gas remaining in the tank when the pressure reaches 10 atm Adiabatic expansion