STUPIDSID
Solve any one question fromQ.1(a,b) and Q.2(a,b)
1(a)
A Pelton turbine develops 3000 kW under a head of 400 m. The overall efficiency of the turbine is 87%. If the speed ration is 0.48 and the coefficient f velocity is 0.96 and specific speed 18, Find
i) Diameter of the turbine
ii) Diameter of the jet.
i) Diameter of the turbine
ii) Diameter of the jet.
6 M
1(b)
Show that the efficiency of a free jet striking normally on a series of flat plates mounted on the periphery of a wheel can never exceed 50%.
4 M
2(a)
The external & internal diameter of an inward flow reaction turbine are 2m & 1m respectively. The head on the turbine is 60m. The width of the vane at inlet & outlet are same and equal to 0.25 m. The runner vanes are radial are inlet & discharge is radial at outlet. The speed is 200 rpm and the discharge is 16m3/s. Determine:
i) The vane angle at outlet and inlet of the runner
ii) The hydraulic efficiency
i) The vane angle at outlet and inlet of the runner
ii) The hydraulic efficiency
6 M
2(b)
Define specific speed of turbine & state its significance.
4 M
Solve any one question fromQ.3(a,b) and Q.4(a,b)
3(a)
Define the term: Degree of reaction and explain the meaning of pure reaction and 50% reaction turbines.
4 M
3(b)
A Kaplan turbine develops 1500kW under a head of 6m. The turbine is set 2.5 m above the tailrace level. A vacuum gauge inserted at the turbine outlet records a suction head od 3.2m. If the turbine efficiency is 85%, what will be efficiency of the draft tube having inlet diameter of 3 m. (Neglect losses in draft tube).
6 M
4(a)
Define the following terms:
i) Diagram efficiency
ii) Nozzle efficiency
i) Diagram efficiency
ii) Nozzle efficiency
4 M
4(b)
In a Parson's turbine running at 1500 rpm, the available enthalpy drop for an expansion is 63kJ/kg. If the mean diameter of the rotor is 100 cm, find the number of moving rows required. Assume that efficiency of a stage is 0.8, blade outlet angle 20° and speed ratio 0.7.
6 M
Solve any one question fromQ.5(a,b,c) and Q.6(a,b)
5(a)
Derive an expression for the minimum speed for starting a centrifugall pump.
6 M
5(b)
Explain different types of casing used in centrifugal pump.
4 M
5(c)
A centrifugal pump delivers 1800 lit / min against a total head of 20 m. Its speed is 1450 rpm. Inner & outer diameters of impeller are 120 mm & 240 mm respectively and the diameter of suction & delivery pipes are both 100 mm. Determine the blade angles of the impeller vane at inlet & outlet respectively if the water enters radially. Assume manometric efficiency is 0.90.
8 M
6(a)
Derive an expression of specific speed of centrifugal pump?
6 M
6(b)
Write a short note on Priming of a centrifugal pump.
4 M
6(c)
A three state centrifugal pump has impellers 50 cm diameter and 3 cm width at outlet. The thickness of the blades has reduced the circumferential area by 10%. The manometric efficiency is 90%, overall efficiency is 80%, whirl velocity at outlet is 20 m/s, velocity of flow at outlet is 2.25 m/s and speed 1000 rpm. Calculate
i) Head generated
ii) Discharge
iii) Exit vane angle
iv) Shaft power
i) Head generated
ii) Discharge
iii) Exit vane angle
iv) Shaft power
8 M
Solve any one question fromQ.7(a,b) and Q.8(a,b,c)
7(a)
Explain the terms surging and choking in a rotary compressor.
6 M
7(b)
The inlet conditions of a centrifugal compressor are 1 bar, 30°C and running at 10000 rpm. It delivers a free air stream of 1.5 m3/s. The compression ration is 5. The velocity of flow is 50 m/s and is constant. Assume that the blades are radial outlet & the slip factor is 0.92, calculate
i) Temperature of air outlet
ii) Power required
iii) Impeller diameter
iv) Diffuser inlet angle
v) Blade angle at inlet
Assume that power factors is 1.11 and isentropic efficiency is 0.90.
i) Temperature of air outlet
ii) Power required
iii) Impeller diameter
iv) Diffuser inlet angle
v) Blade angle at inlet
Assume that power factors is 1.11 and isentropic efficiency is 0.90.
10 M
8(a)
A cetrifugal compressor develops a pressure ratio of 5.0 and an air consumption of 30 kg/s. The inlet temperature and pressure are 15°C and 1 bar repectively. If isentropic efficiency is 0.85, calculate
i) The work done
ii) Exit total temperature
iii) The power required
i) The work done
ii) Exit total temperature
iii) The power required
6 M
8(b)
What do you mean by slip & slip factor? Why diffusers are necessary in a centrifugal compressor?
6 M
8(c)
What is 'Pre-whirl' in centrifugal compressor? Why it is necessary?
4 M
Solve any one question fromQ.9(a,b,c) Q.10(a,b)
9(a)
Compare Axial flow compressor and Centrifugal compressor.
4 M
9(b)
Write a short note on losses in axial flow compressor.
4 M
9(c)
The ambient condtitons at inlet are 20°C and 1 bar. At exit the total head temprature and pressure are 150°C and 3.5 bar, and static pressure at exit is 3 bar. Calculate
i) Isentropic efficiency
ii) Polytropic efficiency
iii) Air velocity at exit
i) Isentropic efficiency
ii) Polytropic efficiency
iii) Air velocity at exit
8 M
10(a)
Represent and expalin the process involved in axial flow compressor on (h-s) diagram And derive an expression for isentropic efficiency and stage pressure ratio.
6 M
10(b)
The speed of an axial flow compressor is 15000 rpm. The mean diameter is 0.6m. The axial velocity is constant and is 225 m/s. The velocity of whirl at inlet is 85 m/s. The work done is 45kJ/ kg of air. The inlet conditions are 1 bar & 300K. Assume a stage efficiecy of 0.89, mechanical efficiency of 0.95 & power developed is 425 kW. Calculate:
i) Fluid deflection angle
ii) Pressure ratio
iii) Mass flow rate
iv) Shaft power
i) Fluid deflection angle
ii) Pressure ratio
iii) Mass flow rate
iv) Shaft power
10 M
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