Question

A Dual cycle engine is analyzed using the cold air standard method. Given the conditions at state 1, compression ratio (r), and cutoff ratio (rc) determine the efficiency and other values listed below.

Note: The specific heat ratio and gas constant for air are given as k=1.4 and R=0.287 kJ/kg-K respectively.

Given Values

T1 (K) = 316

P1 (kPa) = 170

r = 18

rp = 1.44

rc = 1.22

a) Determine the specific internal energy (kJ/kg) at state 1.

b) Determine the temperature (K) at state 2.

c) Determine the pressure (kPa) at state 2.

d) Determine the specific internal energy (kJ/kg) at state 2.

e) Determine the temperature (K) at state 3.

f) Determine the pressure (kPa) at state 3.

g) Determine the specific internal energy (kJ/kg) at state 3.

h) Determine the specific enthalpy (kJ/kg) at state 3.

i) Determine the temperature (K) at state 4.

j) Determine the pressure (kPa) at state 4.

k) Determine the specific enthalpy (kJ/kg) at state 4.

l) Determine the temperature (K) at state 5.

m) Determine the pressure (kPa) at state 5.

n) Determine the specific internal energy (kJ/kg) at state 5.

o) Determine the net-work per cycle (kJ/kg) of the engine.

p) Determine the heat addition per cycle (kJ/kg) of the engine.

q) Determine the efficiency (%) of the engine.

Answer 1

Drawing the P-V diagram correctly and then finding out every point temperature we can solve this question as below-