Question

In: Mechanical Engineering

A combustion process consumes 1.25 g/s of fuel. The fuel has a heat of combustion of...

A combustion process consumes 1.25 g/s of fuel. The fuel has a heat of combustion of 45 MJ/kg.
The air flow rate is 19 g/s and the air enters the engine at 300 K, 1 atm. Determine:

(1) The outlet temperature of the air.

(2) The air-fuel ratio

(3) The heat added to the air.

* Assume the cold-air standard model applies.

Expert Solution

Given,

= 19 g/s = 19 * 10^-3 kg/s

= 1.25 g/s = 1.25 * 10^-3 kg/s

T₁ = 300 K

P₁ = 1 atm

CV = 45 MJ/kg = 45000 kJ/kg

= 1.005 kJ/kg·K

By energy balance, we have

Air-fuel ratio,

Rate of Heat added to the air is equal to the heat supplied by combustion of the fuel.

For per unit time, heat added to air will be equal to 56.25 kJ

samet mamat answered 2 years ago

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