Question

Air enters the compressor of an ideal cold air-standard Brayton cycle at 100 kPa, 300 K, with a mass flow rate of 6 kg/s. The compressor pressure ratio is 7, and the turbine inlet temperature is 1200 K. For constant specific heats with k = 1.4 and Cp = 1.005 kJ/kg, calculate the percent thermal efficiency (enter a number only)

Answer 1

Answer:

The thermal efficiency of cycle is 42.6%.

Explanation:

Given that

$T_1=300 K$

$P_1=100KPa$

mass flow rate = 6 kg/s

Compression ratio = 7

Turbine inlet temperature = 1200 K

γ=1.4

We know that thermal efficiency of Brayton cycle given as

$\eta=1-\dfrac{1}{r_p^{\frac{\gamma-1}{\gamma}}}$

Now by putting the values

$\eta=1-\dfrac{1}{r_p^{\frac{\gamma-1}{\gamma}}}$

$\eta=1-\dfrac{1}{7^{\frac{1.4-1}{1.4}}}$

η=0.426

So the thermal efficiency of cycle is 42.6%.