Subject Code: 2151903
GUJARAT TECHNOLOGICAL UNIVERSITY
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BE- SEMESTER-V (NEW) EXAMINATION - WINTER 2020
Subject Name: Fluid Power Engineering
Time: 10:30 AM TO 12:30 PM
Instructions:
- Attempt any FOUR questions out of EIGHT questions.
- Make suitable assumptions wherever necessary.
- Figures to the right indicate full marks.
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Q.1
(a) Draw general layout of hydro power plant with essential components. (03)
(b) Classify hydro power plant. (04)
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(c) Derive expression of work done for impact of jet on a moving inclined plate. (07)
Q.2
(a) Explain principle of jet propulsion. (03)
(b) Obtain expression for the efficiency and maximum efficiency of jet propulsion when inlet orifices are at right angle to ship. (04)
(c) A jet of water impinges on a symmetrically curved vane at the centre. The velocity of the jet is 60 m/sec and the diameter is 120 mm. The jet is deflected through an angle of 120°. Calculate the force on the vane if the vane is fixed. Also determine the force if the vane moves with a velocity of 25 m/sec in the direction of jet. What will be the power and efficiency? (07)
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Q.3
(a) Differentiate between impulse and reaction hydraulic turbines. (03)
(b) Explain with neat sketch the functions of main components of Pelton turbine. (04)
(c) A Pelton wheel is required to develop 4000 kW at 400 rev/min, operating under net head of 350 m. There are two jets and the bucket deflection angle is 165°. Calculate the bucket pitch circle diameter, the cross sectional area of each jet and the hydraulic efficiency of the turbine. Make the following assumptions (i) overall efficiency is 85% when the water is discharged from the wheel in a direction parallel to the axis of rotation (ii) Co-efficient of velocity of nozzle Kv=0.97 and the blade speed ratio Ku=0.46 (iii) relative velocity of water at exit from the bucket is 0.86 times the relative velocity at inlet: (07)
Q.4
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(a) Compare Francis and Kaplan Turbine. (03)
(b) Derive the equation of hydraulic efficiency of a Pelton turbine. Obtain condition for maximum hydraulic efficiency. (04)
(c) A reaction turbine works at 450 rpm under a head of 120 m. Its diameter at inlet is 120 cm and the flow area is 0.4 m². The angle made by absolute and the relative velocity at inlet are 20° and 60° respectively with a tangential velocity. Determine: (i) volume flow rate. (ii) power developed (iii) hydraulic efficiency. (07)
Q.5
(a) What is pump? Classify Pumps. (03)
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(b) What is cavitation? What are its effects? (04)
(c) The impeller of a centrifugal pump has an external diameter of 450 mm and internal diameter of 200 mm and it runs at 1440 rpm. Assuming a constant flow velocity through the impeller at 2.5 m/s and that the vanes at the exit absolute velocity of water makes with the tangent at the exit and (ii1) The work done per unit weight of water. (07)
Q.6
(a) Define and derive specific speed relation for pump. (03)
(b) Explain submersible pump with advantages and disadvantages. (04)
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(c) Write down difference between Positive displacement pumps and Rotodynamic pumps. (07)
Q.7
(a) Draw a neat sketch, and explain the operation of Hydraulic Accumulator. (03)
(b) What is pre-whirl? Explain the effect of Pre-whirl in centrifugal Compressor. (04)
(c) Explain the effect of blade shape of impellers on performance of Centrifugal compressor. Also classify the blades based on curvature. (07)
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Q.8
(a) Draw a neat sketch, and explain the operation of Hydraulic Crane. (03)
(b) Give comparison between axial flow and centrifugal compressor. (04)
(c) A centrifugal compressor running at 12000 rpm delivers 1.3 m³/s of free air. The pressure and temperature at inlet are 1 bar and 25°C. The compression ratio is 5, blades are radial at outlet, the velocity of flow is 58 m/s and is constant throughout. Assume slip factor is 0.9 and isentropic efficiency is 84 %. Determine (i) temperature of air at outlet, (ii) impeller diameter and blade angle at inlet and (iii) power required. Assume inlet diameter of impeller half of outlet diameter of impeller. (07)
Date: 03/02/2021
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Total Marks: 56
This download link is referred from the post: GTU B.Tech 2020 Winter Question Papers || Gujarat Technological University
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