Question

7.4 A complex Brayton-cycle power plant using intercooling, reheat, and regeneration is analyzed using the air standard method. Air is compressed from State 1 to State 2 using a compressor with a pressure ratio of RP1. An intercooler is used to cool the air to State 3 before entering a second compressor with a pressure ratio of RP2. The compressed air exits at State 4 and is preheated in a regenerator that uses the exhaust air from the low-pressure turbine. The preheated air enters the combustor at State 5 and is heated to State 6 where it enters the high-pressure turbine. The air exits the turbine at State 7 and is heated in a reheat combustor to State 8. The air expands in a low-pressure turbine to State 9 where it enters the counterflow regenerator with the effectiveness of RE. Given the specified operating conditions determine the efficiency and other values listed below.

--Given Values--

T1 &T3 (K) = 303

P1 (kPa) = 186

rp1 = 2.7

rp2 = 4.4

Eff (%) = 92

T6 & T8 (K) = 1300

P7 (kPa) = 906

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.

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

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

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

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

i) Determine the relative pressure at state 3.

j) Determine the relative pressure at state 4.

k) Determine the temperature (K) at state 4

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

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

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

o) Determine the specific enthalpy (kJ/kg) at state 6.

p) Determine the relative pressure at state 6.

q) Determine the relative pressure at state 7.

r) Determine the temperature (K) at state 7.

s) Determine the specific enthalpy (kJ/kg) at state 7.

t) Determine the specific enthalpy (kJ/kg) at state 8.

u) Determine the relative pressure at state 8.

v) Determine the relative pressure at state 9.

w) Determine the specific enthalpy (kJ/kg) at state 9.

x) Determine the net work per unit mass (kJ/kg) through the power plant.

y) Determine the heat addition per unit mass (kJ/kg) through the power plant.

z) Determine the efficiency () of the power plant.

Answer 1