1. Define turbo machines and explain the different types of turbo machines.
2. “The energy transfer as work per unit mass flow numerically equal to change in stagnation enthalpy of the fluid between the turbo machine inlet and outlet”. Discuss the above in the light of laws of thermodynamics for turbo machine.
3. What are the applications of first laws and second of thermodynamics.
4. Define degree of reaction and derive a general expression for the degree of reaction.
5. At a stage of an impulse turbine, the mean blade diameter is 75 cm, rotational speed 3500 r. p. m. The absolute velocity of fluid discharging from nozzle inclined at 200 to the plane of wheel is 275 m/sec. if the utilization factor is 0.9 and the relative velocity at the rotor exit is 0.9 times that at inlet, find the inlet and exit rotor angles. Also find the power output from the stage for a mass flow rate of 2 kg/s and axial thrust on the shaft.
1. What do you mean by Governing?
2. Discuss the various methods of steam turbine governing.
3. Why reaction stages are preferred in comparison to impulse stages in steam turbines?
4. A turbine is supplied with steam at 35 bar and a temperature of 4350C. It is expanded in four stages to the condenser pressure of 0.04 bar. The pressure at the end of stage are 5, 12 and 0.25 bar respectively. Loss due to friction throughout the expansion is 24%. Determine :
a. The isentropic enthalpy drop in each stage
b. The enthalpy drop for the turbine if friction is neglected
c. The work done in kJ/kg of flow neglecting all losses other than the one stated above
d. The reheat factor.
5. In a Curtis steam turbine stage, there are two row of moving blades with equiangular rotors. Steam enters the first rotor at and angle of 290 each and second rotor at an angle of 320 each. The absolute velocity of steam as it enters the first rotor is 530 m/sec. and the blade velocity coefficient is 0.9 in the first rotor 0.91 in stater and 0.93 in the second rotor. If the final discharge should be axial, determine (i) the power output for a steam flow rate of 3.2 kg/sec and (ii) the axial thrust.
1. A Kaplan turbine develops 15MW of power at a head of 30m. The diameter of the hub is 0.35 times the diameter of the runner. Asuming a speed ratio of 2 flow ratio of 0.65 and overall efficiency of 90% calculate (a) diameter of the runner (b) rotational speed (c) specific speed of the turbine
2. A Kaplan turbine has arunner of 4m diameter and hub of 1.2m dia. The discharge through the turbine is 70m3/s. The hydraulic and mechanical efficiencies can be assumed to be 0.9 and 0.93 respectively. Assuming the absence of whirl at the outlet estimate (a) net available head on the turbine (b) power developed . If the speed ratio is 2 estimate the specific speed of the turbine.
3. The following data are available for Francis turbine:
Flow velocity (constant) =4m/s
Peripheral velocity at inlet=30m/s
Whirl velocity at inlet= 25m/s
Assuming hydraulic efficiency of 90% and zero whirl at the exit, determine (a) the head available to the turbine (b) inlet blade angle (c) inlet guide vane angle
4. Write short notes on any two:
a) Kaplan Turbine
b) Manometric Head, static and Gross Head
d) Governing of Water Turbines
5. Explain the significance of Hydraulic, Volumetric and overall efficiency of centrifugal pumps.
1. Define the following:
a. Slip factor
b. Power input factor
c. Pressure coefficient in the centrifugal compressor
2. Explain the basic principle of axial flow compressor.
3. Describe the working of centrifugal compressors. What do you understand by surging and choking phenomenon?
4. Compare the axial flow compressor with centrifugal compressors.
5. A centrifugal compressor handles 600kg/min of air. The ambient air conditions are 1 bar and 27oC. The compressor runs at 18000 rpm with an isentropic efficiency of 80%. The air is compressed from 1 bar to 4 bar. The air enters the impeller eye with a velocity of 150m/s. Take the ratio of whirl speed to tip speed as 0.9. Calculate
a) The rise in total temperature during compression if change in kinetic energy is negligible.
b) Tip diameter of impeller
c) Power required
d) Eye diameter if hub diameter is 10 cm.
1. A source of water can supply 90 litres/s under a head of 5m to a hydraulic ram pump. Estimate the discharge that can be delivered to a tank situated 24m above the pump. Assume an efficiency of 40% for the pump. The friction head in the supply pipe and delivery pipe are 0.2m and 0.7m respectively.
2. Write Short notes on Hydraulic intensifier with diagram.
3. An accumulator has ram 300mm in diameter and an effective stroke of 6 m and is loaded with total weight of 490.5 KN. If the friction of ram amount of 3% of the total load find the total power delivered to the hydraulic machine, if the ram falls steadily through its full stroke in 2 minutes while at the same time the pump delivers 7.5 litres/sec.
4. Draw a neat sketch of fluid coupling. State component details and working.
5. A source of water can supply 90 litres/s under a head of 5m to a hydraulic ram pump. Estimate the discharge that can be delivered to a tank situated 24m above the pump. Assume an efficiency of 40% for the pump. The friction head in the supply pipe and delivery pipe are 0.2m and 0.7m respectively.