JNTU
JNTU B.Tech II FLUID MECHANICS AND HYDRAULIC MACHINES Previous Question Paper (November/December - 2018 - R16)
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 a fluid? How are fluids classified?
Answer
A fluid is a substance that deforms continuously under the application of a shear stress, no matter how small the stress may be. Fluids are classified into ideal fluids (incompressible and non-viscous) and real fluids (possess viscosity and compressibility).
What is a Newtonian fluid?
Answer
A Newtonian fluid is a fluid in which the shear stress is directly proportional to the rate of angular deformation or velocity gradient. This relationship is defined by Newton's Law of Viscosity:
where τ is shear stress, μ is the dynamic viscosity, and du/dy is the velocity gradient.
Define stream tube and streak lines.
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Define laminar and turbulent, rotational & irrotational flows.
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Explain the term boundary layer.
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What is an equivalent pipe?
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What is a surge tank?
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On what factors does the cavitation in water turbines depend?
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How are pumps classified?
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What is NPSH?
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Part B
Explain briefly the following: i) Surface tension ii) compressibility.
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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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Explain briefly the following terms: i) Mass density ii) Weight density iii) Specific volume iv) Specific gravity.
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A simple manometer containing mercury is connected to a pipe in which an oil of specific gravity 0.8 is flowing. The pressure in the pipe is vacuum. The other end of the manometer is open to atmosphere. Find the vacuum pressure in pipe, if the difference of mercury level in the two limbs is 200mm and height of oil in the left-limb from the centre of the pipe is 150mm below.
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State and prove Bernoulli’s equation. What are its limitations?
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Explain how momentum equation is used in the analysis of forces on pipe bend.
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Show that the streamlines and equipotential lines form a net of mutually perpendicular lines.
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The velocity potential function for a two-dimensional flow is. at a point P(4, 5) determine: i) The velocity and ii) The value of stream function.
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Explain briefly the following: i) Hydraulic gradient line (H.G.L.) ii) Total energy gradient line (T.G.L.)
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The discharge of water through a horizontal pipe is 0.25m3/s. Its diameter, which is 200mm, suddenly enlarges to 400mm. If the intensity of pressure of water in the smaller pipe is 120kN/m2, determine: i) Loss of head due to sudden enlargement ii) Intensity of pressure in the large pipe and iii) Power lost due to enlargement.
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Explain boundary layer in transition.
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A main pipe divides into two parallel pipes which again forms one pipe. The length and diameter for the first parallel pipe are 2000m and 1.0m respectively, while the length and diameter of the second pipe are 2000m and 0.8m respectively. If the total flow in the main is 3m3/s and the co-efficient of friction for each pipe is same and equal to 0.005, find the rate of flow in each parallel pipe.
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Which points should be considered while selecting right type of hydraulic turbines for hydroelectric power plant?
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A nozzle of 50mm diameter delivers a stream of water at 20m/s. perpendicular to a plate that moves away from the jet at 5m/s. find:
The force on the plate,
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The work done and
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The efficiency of jet.
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Define indicator diagram. Prove that work done by the pump is proportional to the area of indicator diagram.
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Derive an expression for the work done by the impeller of a centrifugal pump on liquid per second per unit weight of liquid.
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Define slip, percentage slip and negative slip of a reciprocating pump.
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