JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III MECHANICS OF FLUIDS AND HYDRAULIC MACHINES Previous Question Paper (November/December - 2017 - R13)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
What is kinematic viscosity? What are its units?
Answer
Kinematic viscosity is defined as the ratio of dynamic viscosity to the mass density of the fluid. It is denoted by the symbol ν. Its SI unit is m²/s and the CGS unit is Stokes (1 Stoke = 10⁻⁴ m²/s).
Define the term static head and manometric head.
Answer
Static head is the vertical distance between the suction level and the delivery level of a pump. Manometric head is the actual head against which a pump has to work, calculated as the sum of suction head, delivery head, and head losses (including friction and velocity head) in the system.
Define the term streak lines?
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What is velocity head?
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What is a pitot tube?
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Write a note on flow nozzle.
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Where is Kaplan turbine used?
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What is a surge tank?
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What is an air vessel?
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What is NPSH?
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Part B
State and prove Pascal’s law.
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A U-tube differential manometer is used to measure the difference of pressure between inlet throat of a venturimeter placed with its axis horizontal in a pipe line. Calculate the difference in pressure between inlet and throat when the manometer reading is 250mm and water flows through the pipe.
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Describe giving a sketch, a micro manometer. Explain how it could be used for measuring small pressure difference.
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A liquid has a specific gravity of 1.9 and kinematic viscosity of 6 stokes. What is its dynamic viscosity?
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Write briefly about the classification of flows?
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250 litres/sec of water is flowing in a pipe having a diameter of 300mm. If the pipe is bent by 135°, find the magnitude and direction of the resultant force on the bend. The pressure of the water flowing is 400kN/m2. Take specific weight of water as 9.81kN/m3.
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State and derive continuity equation for one dimensional flow.
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The water is flowing through a pipe having diameters 200mm and 100mm at sections 1 and 2 respectively. The rate of flow through the pipe is 35 litres/s. The section 1 is 6m above the datum and section 2 is 4m above the datum. If the pressure at section 1 is 400kN/m2, find the intensity of pressure at section 2.
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Derive formulae for calculating loss of head due to i) Sudden enlargement ii) Sudden contraction
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A horizontal pipe of 100mm diameter is joined sudden enlargement to a 150mm diameter pipe. Water is flowing though it at the rate of 2m3/min. find: i) Loss of head due to abrupt expansion ii) Pressure difference in two pipes and iii) Change in pressure if the change of section is gradual, without any loss.
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Explain the terms total energy line and hydraulic gradient line.
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Show that for velocity distribution, the ratio of δ/δ* = 3.
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A Kaplan turbine produces 44000kW under a head of 24.7m, with an overall efficiency of 90 percent. Taking the value of speed ratio as 1.6, flow ratio as 0.5 and the hub diameter as 0.35 times the outside diameter, find the runner diameter and speed of the turbine.
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The angles of curved vane tips so that water enters and leaves without shock;
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The work done per N of water entering the vane.
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Draw an indicator diagram, considering the effect of acceleration and friction in suction and delivery pipes. Find an expression for the work done per second in case of single acting reciprocation pump.
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What is negative slip in reciprocating pump? Explain with neat sketches the function of air vessels in a reciprocating pump.
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