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Unformatted text preview: MECH 3020 Thermodynamics II: Homework Set 10 1. A gas mixture consists of 6 parts helium to 2 parts octane vapor on a volumetric basis. The mixture is initially at 300 K, 1 atm. (a) Using tabulated specific heat data, calculate the specific gas constant and mass-based specific heat c P for the mixture. (b) Say the mixture is compressed adiabatically and reversibly to 5 atm pressure. Assuming constant specific heats, calculate the temperature of the mixture at the end of the compression process. Properties are c p, He = 5 . 19 kJ / kg K , M He = 4 kg / kmol c p, ov = 1 . 71 kJ / kg K , M ov = 114 . 2 kg / kmol Volume fractions are equivalent to mole fractions: y He = 0 . 75 , y ov = 0 . 25 M = y He M He + y ov M ov = 31 . 55 kg / kmol R = R u M = 0 . 264 kJ / kg K c P = 1 M ( y He M He c P, He + y ov M ov c P, ov ) = 2 . 41 kJ / kg K The ratio of specific heats is k = c P c v = c P c P- R = 1 . 14 and, for the isentropic compression, T 2 = T 1 P 2 P 1 ( k- 1) /k = 369 . 3 K 2. A 0.2 m 3...
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This note was uploaded on 09/24/2011 for the course MECH 3020 taught by Professor Mackowski during the Spring '11 term at Auburn University.
- Spring '11