Question

5. The Martian atmosphere consists mainly of carbon dioxide with an average surface pressure of 700. Pa and an average temperature of -57 °C. A piston-based compressor is being designed to take ambient Martian gas and increase the pressure to 2.2 bar before it is processed for rocket fuel. CO2 is not CPG at these conditions -- you can assume it to ONLY be a TPG gas. a. Assuming the Mars atmosphere is pure CO2 and the compression process is isentropic, what would be the temperature of the gas after compression. b. Determine the minimum amount of work per kg of gas required to perform this isentropic compression process. (part b is an extra credit problem - 5 points)

Answer 1

P, = 7oo Pa 9,= -51°C = 216k - P2 = 2 bar T 2 - Seotropic Relation - Bentopic relation 1.289-1 1.289 216 too up T2 = 767.57 K t Final temperature for Ti (216k), hi = 6466.2 kul kmol = 46.96 latky Tz (767.5), z = 30517.4 kl knol = 693-6 kolka (6) Minimum work done a bachi = 546.64 kolka = 693.6 -146.96