Question

An inventor proposes a four-stroke cycle running on helium. The engine has a compression ratio of 8 and maximum operating temperature of 1,500 K. The atmospheric

conditions are temperature of 300 K and pressure of 100 kPa. The processes can be approximated as below:

1- 2 isentropic compression

2- 3 constant volume heat addition

3- 4 isentropic expansion

4- 1 constant pressure heat removal

a. Plot P-v and T-s diagrams for this cycle.

b. Determine state conditions at the end of each step by filling up the table below.

c. Heat addition

d. Net work

e. Thermal efficiency

Hint:

Cp = 5.193 kJ/kg.K,

Cv = 3.116 kJ/kg.K,

R = 2.077 kJ/kg.K,

k = 1.667

Answer 1