During the trial of a single-acting oil engine, cylinder diameter 20 cm, stroke 28 cm, working on the two-stroke cycle and firing every cycle, the following observations were made:
Duration of trial = 1 hour
Total fuel used = 4.22 kg;
Calorific value = 44670 kJ/kg;
Proportion of hydrogen in fuel = 15%
Total number of revolutions = 21000
Mean effective pressure = 2.74 bar
Net brake load applied to a drum of 100cm diameter = 600N
Total mass of cooling water circulated = 495 kg
Temperature of cooling water:
Inlet 130 °C, outlet 38°C
Air used, 135 kg.
Temperature of air in test room, 20°C and Temperature of exhaust gases, 370°C
Assume:
CPgases = 1.005 kJ/kgK and CPsteam at atmospheric pressure = 2.093 kJ/kg K.
Calculate the thermal efficiency and draw up the heat balance.