1)
An oil engine works on Diesel cycle, the
compression ratio being 15. The temperature at the
start of compression is 17°C and 700 kJ of heat is
supplied at constant pressure per kg of air and it
attains a temperature of 417°C at the end of adiabatic
expansion. Find the air-standard efficiency of the
cycle. What would be the theoretical work done per
kg of air. Take C, = 0.717 kJ/kgk and y = 1.4. .
Answers
Explanation:
3.11 An oil engine works on Diesel cycle, the compression ratio being 15. The temperature at the start of compression is 17 °C and 700 kJ of heat is supplied at constant pressure per kg of air and it attains a temperature of 417 °C at the end of adiabatic expansion. Find the air-standard efficiency of the cycle. What would be the theoretical work done per kg of air. Take Cu 0.717 kJ/kg K and γ-- 1.4. 9.19 A compression-ignition engine has a compression ratio of 10 and 2/3 of heat of combustion is liberated constant volume and the remainder at constant pressure. The pressure and temperature at the beginning 1 bar and 27°C and the maximum pressure is 40 bar. Find the temperature at the end of compression [Ans. 398.6°C, 347.3 expansion, if it follows the law pv1.35-constant, and γ-1.4. 5. The following observations were made during a test on a single cylinder four-stroke oil engine: Displacement volume 3 litre; speed of the engine 600 rpm; fuel consumption = 2.9 kg/h; calorific value of fuel - 42,500 kJ/kg; difference in tension on either side of the brake pulley 450 N; arm length 0.35 m; length of indicator diagram 60 mm; area of positive loop of indicator diagram 580 mm2; area of negative loop 30 mm2; spring constant 0.85 bar per mm. Calculate (a) bp (b) ip (c) Mechanical efficiency (d), brake thermal efficiency (e) bsfc. 20