Internal Combustion Engines & Steam Engines
An engine operating on the Otto cycle has a stroke length of 100 mm and a piston diameter of 50 mm. What is the maximum clearance volume which will give an air standard efficiency of 60%?
2. A single cylinder diesel engine produces an output torque of 75 Nm when running at 1600 revs min–1. The indicated mean effective pressure in the cylinder is 5 bar and the piston diameter and stroke length are 150 mm and 250 mm respectively. Calculate :
(a) The mechanical efficiency of the engine
(b) The brake mean effective pressure.
3. Given that the internal energy of water at 28 bar pressure is 988 kJ kg–1 and that the specific volume of water at this pressure is 0.121 × 10–2 m3 kg–1, calculate the specific enthalpy of water at 55 bar pressure.
4. A rigid vessel with a volume of 0.75 m3 contains steam at 1.8 MN m-2 and 450°C. The vessel is cooled until the steam pressure is 8 bar. Calculate:
(a) The mass of steam present.
(b) The final dryness fraction. Use the simplified method of calculation where vf is taken as zero.
(c) The heat transfer for the process.
5. A horizontal steam turbine is supplied with steam at 15 bar and 300°C through a pipe 400 mm in diameter. The mass flow rate of the steam is 5 kg s-1. The steam leaves the turbine at 0.75 bar and 150°C with a velocity of 100m s-1. The steam loses heat at a rate of 15kJ kg-1 as it passes through the turbine. Determine:
(a) The velocity of the steam as it passes down the pipe into the turbine.
(b) The power output of the turbine.