A four-stroke diesel engine operates on liquid Decane fuel (C10H22). The air and fuel enter the engine at 25°C and the fuel flow rate is 3.391 x 10?³ kg.s?¹. During a particular steady state test, the exhaust gas temperature was measured at 227°C and the gas composition in the exhaust manifold was determined (on a dry volumetric basis) as; CO?: 9.31% CO: 0.19% O?: 6.98% NO: 0.95% N?: 82.57% The engine power output was measured at 60.0 kW. Determine; (i) the brake thermal efficiency of the engine, (6 marks) (ii) the air-fuel ratio on a mass basis, (10 marks) (iii) the rate of heat rejection to atmosphere via engine coolant and radiation losses. (10 marks) Decane (C10H22) Liquid Fuel; Molar mass C10H22 = 142 kg.kmol?¹ Enthalpy of formation C10H22 liquid = -301,000 kJ.kmol?¹ Enthalpy of combustion C10H22 liquid = -44,240 kJ.kg?¹ (vapour water in products)
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The fuel flow rate is given as 3.391 x 10^-3 kg/s. To find the fuel input per second, we multiply the flow rate by the molar mass of Decane (C10H22): Fuel Input = (3.391 x 10^-3 kg/s) * (142 kg/kmol) = 0.482 kg/kmol Show more…
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