Calculate: Brake thermal efficiency

Question

The air flow to a four cylinder 4-stroke oil engine is measured by means of a 4.5 cm diameter orifice, having C_d = 0.65. During a test the following data was recorded:

Bore = 10 cm, Stroke = 15 cm,

Engine speed = 1000 RPM,

Brake torque = 135 Nm,\fuel consumption = 5.0 kg/our,

CV_fuel = 42600 kJ/kg, Head across orifice = 6 cm of water, Ambient temperature and pressure are 300 K and 1.0 bar respectively. Calculate:

1. Brake thermal efficiency
2. The brake mean effective pressure
3. The volumetric efficiency

Take R = 2.87 J/kg K for air.                                                                                             30