A calorically perfect gas (specific heat at constant pressure

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A calorically perfect gas (specific heat at constant pressure 1000 J/kgK) enters and leaves a gas turbine with the same velocity. The emperature of the gas at turbine entry and exit are 1100 K and 400 K, respectively. The power produced is 4.6 MW and heat escapes at the rate of 300 kJ/s through the turbine casing. The mass flow rate of the gas (in kg/s) through the turbine is

1. 6.14
2. 7.00
3. 7.50
4. 8.00

Correct Option: B

m

h₁ +

C²₁

gz₁

+ Q = m

h₂ +

C²₂

gz₂

+ w

2

2

m (h₁ – h₂) + Q = w
m (700) (1000) = (4600 + 300) ×103 J/s = 7kg/s