1)(a) describe the flow pattern from leading to trailing edge of a cambered aerofoil blade in a turbo Machine.
(b) Describe the Reheat and Preheat phenomena in Turbines and Compressors.
2)(a) Low Pressure air Compressor develops the pressure of 1500 kgf/m2. If initial and final states of air P1 = 1.02 bar, T1 = 300K and T2 = 315 K. Find out the compressor and infinitesimal stage efficiencies.
(b) prepare down the losses in turbo Machines.
3) A centrifugal fan has the data given below:
Inner Diameter of the impeller = 18 cm
Outer diameter of the impeller = 20 cm
Speed = 1450 rpm
Relative and absolute velocities respectively are:
At Entry = 20 m/s, 21 m/s
At exit = 17 m/s, 25 m/s
Flow rate = 0.5 kg/s
Motor efficiency = 78%
(a) the stage pressure rise
(b) Degree of reaction
(c) The power required to drive the fan
Take density of air 1.25 kg/m3.
4) The axial fan stage consisting of only the rotor has the following data:
Rotor blade air angle at exit = 10o
Tip Diameter = 60cm
Hub Diameter = 30 cm
Rotational Speed = 960 rpm
Power required = 1 KW
Flow co-efficient = 0.245
Inlet flow conditions (P1) = 1.02 bar
Inlet flow conditions (T1) = 316 K
(a) the rotor blade angle at entry
(b) Stage pressure rise
(c) Overall efficiency
5) Stage of a turbine with Parsons blading delivers dry saturated steam at 2.7 bar from fixed blades at 90 m/s. Mean blade height is 40 mm, and moving blade exit angle is 20o. Axial velocity of steam is ¾ of the blade velocity at mean radius. Steam is supplied to the stage at the rate of 9000 kg/hr. The effect of blade tip thickness on the annulus area can be neglected, compute
(a) the wheel speed in rpm
(b) the diagram power
(c) the diagram efficiency