Jawaharlal Nehru Technological University Hyderabad 2011-2nd Year B.E Electrical and Electronics Engineering B.TECH - FLUID MECHANICS AND HYDRAULIC MACHINERY (EM 1) - Question Paper

FLUID MECHANICS AND HYDRAULIC MACHINERY
(ELECTRICAL AND ELECTRONICS ENGINEERING)
Time II B.TECH - I SEMESTER exams - MAY, 2011
: 3hours Max. Marks: 75
ans any 5 ques.
All ques. Carry Equal Marks
- - -
1.a) discuss the fluid property vapour pressure. provide its significance in Engineering. A body weighing 450 N with a flat surface area of 0.023m2 slides down lubricated inclined plane making a 300 angle with the horizontal. For viscosity of 0.1 N-S/m2 and body speed of 3m/s, determine the lubricant film thickness.
b) What is the difference ranging from simple manometer and differential manometer? A closed tank as shown in figure one is filled with water and is two m long. The pressure gauge on the tank reads 50N/m2. Determine:
i) Height 'h' in the open water column.
ii) Absolute pressure of the air on the water surface if local atmosphere pressure is 101N/m2.
iii) Gauge pressure acting on the bottom surface AB of the tank. [7+8]
Figure one
2.a) describe continuity formula & derive the expression for the identical for on dimension flow. The velocity componals for 2 dimensional, steady static and incompressible flow field are provided by U = Cxy and V = C loge(xy). Check whether the flow exist or not?
b) Water is supplied to a turbine through a 0.3 m diameter pipe at the rate of 0.3m3/s. After passing through the turbine water is discharged through a draft tube which has a diameter of 0.6m at point B which is 1m beneath a point A in the 0.3m pipe. If the pressure at the points A and B are respectively 147.15 kN/m2 and -34.335 kN/m2. Determine the power delivered to the turbine by the water. [8+7]
3.a) define Reynold's experiment and state the significance of Reynold's number. Pipes of 500 mm diameter, 1800m length, 400 mm diameter, 1200 m length and 300 mm diameter, 600 m length are connected in series. If these pipes are to be changed by an equivalent pipe of 400 mm diameter, what would be its length?
b) A pilot tube records a studying of 7.85 kN/m2 as the stagnation pressure when it is held at the centre of a pipe of 250 mm diameter conveying water. The state pressure is the
discharge 40 mm of mercury (gauge – vacuum). compute the discharge through the pipe assuming that the mean velocity of flow is 0.8 times the maximum velocity, take Cd = 0.98. [7+8]
4.a) find an expression for force existed by a jet of water on an unsymmetrical moving curved plate when the jet strikes tangentially at 1 of the tips.
b) A 50 mm diameter jet having a velocity of 25m/s, strikes a flat plate, the normal of which is incline at 300 to the axis of the jet compute the normal force exerted on the plate, when the plate is moving with a velocity of 10 m/s in the direction of the jet. obtain also the work done and the efficiency of the jet when the plate is moving. [7+8]
5.a) discuss Run off river plants, Reservoir plants, pumped storage plants & Tidal plants.
b) How mass curve technique is used to determine the capacity of reservoir to satisfy the uniform demand of water. [7+8]
6.a) Prove for a pelton wheel turbine, the hydraulic efficiency is maximum when the bucket speed is equal to half the velocity of jet and find the expression for the maximum hydraulic efficiency with usual notation.
b) The diameter of an inward radial flow turbine is 1.2 m and inward flow area is 0.5 m2. The head available is 150 m. The inlet vane angle and blade angle are 200 and 600 respectively. If the turbine is running at 500 rpm, obtain out the power developed by the turbine and hydraulic efficiency. presume discharge passing through the runner.
[7+8]
7.a) What is a Surge tank and a fore bay and elaborate their functions? define with neat sketches various kinds of surge tank?
b) A hydraulic turbine develops 7355 kW of power under a head of 24.7m at 210 rpm. What is its specific speed? Indicate the kind of turbine suitable for the purpose if this turbine is tested in the laboratory where the head available is 7.5 m, what power will if develop and at what speed? [7+8]
8.a) describe Manometric efficiency, volumetric efficiency, mechanical efficiency, overall efficiency as applied to centrifugal pump.
b) The inner and outer diameters of an impeller of a centrifugal pump are 250 mm and 500 mm respectively. The velocity of flow at outer is 1.5 m/s and vane outlet angle 600. If the manometric efficiency is 75%, final out the minimum speed needed to begin the flow. [7+8]

Earning:   Approval pending.