Question

7.2 A Brayton cycle gas engine is analyzed using the air standard method. Given the conditions at state 1, pressure ratio (rp), and cutoff ratio (rc) determine the efficiency and other values listed below. The specific heat ratio and gas constant for air is given as k=1.4 and R=0.287 kJ/kg-K respectively.

T1 (K) = 333

P1 (kPa) = 170

rp = 10.7

rc = 2.54

AV (m3/s) = 1.7

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

b) Determine the relative pressure at state 1.

c) Determine the relative pressure at state 2.

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

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

f) Determine the specific enthalpy (kJ/kg) at state 2.

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

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

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

j) Determine the relative pressure at state 3.

k) Determine the relative pressure at state 4.

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

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

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

o) Determine the mass flow rate (kg/s) through the engine.

p) Determine the net power output (kW) for the engine.

q) Determine the rate of heat addition (kW) for the engine.

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

Answer 1