contestada

A sports car engine delivers 150 kW to the driveshaft with a thermal efficiency of 20%. The fuel has a heating value of 35 000 kJ/kg. Find the rate of fuel consumption and the combined power rejected through the radiator and exhaust.

Respuesta :

Answer:600 kW

Explanation:

Given

Power delivered [tex]P=150 kW[/tex]

Fuel heating value [tex]q=35,000 kJ/kg[/tex]

thermal Efficiency [tex]\eta =\frac{Power}{Heat}[/tex]

[tex]0.2=\frac{150}{35,000\times \dot{m}}[/tex]

where, [tex]\dot{m} =mass\ flow\ rate\ of\ fuel[/tex]

[tex]\dot{m}=\frac{150}{35,000\times 0.2}[/tex]

[tex]\dot{m}=0.0214 kg/s[/tex]

For an Engine

[tex]q\dot{m}=P+Q_r , where Q_r=heat\ rejected[/tex]

[tex]Q_r=q\dot{m}-P[/tex]

[tex]Q_r=750-150=600 kW[/tex]