In: Mechanical Engineering
1) A reciprocating compressor has two stages with inlet air going into LP stage at 1 bar, 16°C and at the rate of 12 m3/min. Air is finally delivered at 7 bar and there is perfect intercooling at optimum pressure between the stages. The index for compression is 1.25 and compressor runs at 600 rpm. Neglecting clearance volume determine intermediate pressure and total power required.
2) A reciprocating compressor of single stage and double acting type has free air delivered at 14 m3/min measured at 1.013 bar, 288 K. Pressure and temperature at suction are 0.95 bar and 305 K. The cylinder has clearance volume of 5% of swept volume. The air is delivered at pressure of 7 bar and expansion and compression follow the common index of 1.3. Determine the volumetric efficiency with respect to free air delivery.
3)1)Single stage impulse turbine has equal blade angles and nozzle angle of 15°. Determine the maximum possible blade efficiency if the blade velocity coefficient is 0.85. Determine the blade speed to steam velocity ratio if the actual blade efficiency is 90% of maximum blade efficiency.
4) The velocity of steam entering a simple impulse turbine is 1000 m/s, and the nozzle angle is 200. The mean peripheral velocity of blades is 400 m/s and the blades are symmetrical. If the steam is to enter the blades without shock, what will be the blade angles. Neglecting the friction effects on the blades, calculate tangential force on the blades and the diagram power for a mass flow of 0.75 kg/s. Estimate axial thrust & diagram efficiency.
5)1)Single stage impulse turbine has equal blade angles and nozzle angle of 15°. Determine the maximum possible blade efficiency if the blade velocity coefficient is 0.85. Determine the blade speed to steam velocity ratio if the actual blade efficiency is 90% of maximum blade efficiency.