Heat transfer of a polytropic process for ideal gas n=0 Cp =KCy Energy balance (1st law): n=1 Cr→0 (ideal gas,n≠1) n=k -(区-0+-W n=士o0 n-K L-T) n-1 q=△u+w !No m,V→v (ideal gas,n=1) V2 =c,(T-T)+RT In Because“w' V instead of“W, g-Tn R 上游充通大 March 23,2018 6 SHANGHAI JIAO TONG UNIVERSITY
March 23, 2018 6 Heat transfer of a polytropic process for ideal gas 2 1 2 1 2 1 2 1 1 1 1 1 v v R R n T T c T T n n R c T T T T n Energy balance (1st law): (ideal gas, n≠1) q u w n c 0 p v n c c 1 T n c 0 s n k c v n c (ideal gas, n=1) 2 2 1 1 2 2 1 1 ln ln 1 v T T v c T T RT v R v RT v !! No m, V v Because “w” instead of “W
Energy relationship w/q of polytropic process 6 (ideal gas,n≠1) R W K-1 西) K-n q=- Expan.,Absorb;Compr.,Reject K-1 n<K >0 >0 W 膨胀，吸热；压缩，放热 K-n q K-1 n>K ≤0 w<0 膨胀，放热；压缩，吸热 K-n q Expan.,Reject;Compr.,Absorb 上游通大学 March 23,2018 7 SHANGHAI JIAO TONG UNIVERSITY
March 23, 2018 7 Energy relationship w/q of polytropic process 1 2 1 2 2 1 1 1 1 1 v v R w T T c T T n n n q c T T n 0 0 1 q w n n w 1 q n 0 0 1 q w n n (ideal gas, n≠1) 膨胀,吸热; 压缩, 放热 Expan., Absorb; Compr., Reject 膨胀,放热; 压缩, 吸热 Expan.,Reject; Compr., Absorb