Constant Cp Cv Ideal gas const.specific heat: 0 s(T2.v2)--5(Ti,v1)=co In+R In T V ->0 T2 sIP-Tp）=Gl P2 pi Ideal gas const.specific heat isentropic: 0 (k-1)/k T2 P2 巧刀 (s=S2,constant k) 0= kR Pi Cp= -- k-I T (s1=S2,constant k) 0= 02 R T D Ui Co= k-1 P2 (S1 S2,constant k) P 上游气通大粤 Tuesday,April 18,2017 6 SHANGHAI JIAO TONG UNIVERSITY
Tuesday, April 18, 2017 6 Constant cp , cv Ideal gas + const. specific heat: Ideal gas + const. specific heat + isentropic: 0 0
Polytropic process (s1 S2.constant k) 。pwk= constant a polytropic process of an ideal gas with constant k is an isentropic process. n=-1 n =k n=±oo v=constant n=-1 n=0 n=0 p constant n=1 T=constant constant n=1 n=士o n=k S 图 上游充通大 Tuesday,April 18,2017 7 SHANGHAI JIAO TONG UNIVERSITY
Tuesday, April 18, 2017 7 Polytropic process a polytropic process of an ideal gas with constant k is an isentropic process