JNTU
JNTU B.Tech II CHEMICAL ENGINEERING FLUID MECHANICS Previous Question Paper (December - 2018 - R15)
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 dilatant fluid? Give example.
Answer
A dilatant fluid is a non-Newtonian fluid whose apparent viscosity increases with an increase in the shear rate (shear-thickening behavior). An example is a concentrated suspension of cornstarch in water.
What is the effect of temperature on viscosity?
Answer
The effect of temperature on viscosity depends on the state of the fluid. For liquids, viscosity decreases as temperature increases because the cohesive forces between molecules weaken. For gases, viscosity increases as temperature increases due to the rise in molecular kinetic energy and the frequency of intermolecular collisions.
What is form friction?
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What is vena contracta?
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What is Mach number?
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Write the difference between compressible and incompressible fluid.
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What is Darcy’s law?
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Write the significance of Burke – Plummer equation.
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Write the use of gate valve and globe valve.
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Write the use of pitot tube.
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Part B
What is rheology? Explain the rheological properties of fluids with examples.
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What is the significance of continuity equation?
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Oil having specific gravity 0.8 is flowing in a tapered pipe line. The velocity at a section having 0.15 m2 area is found to be 2 m/s. Calculate the diameter of the pipe line at which the velocity is 2.7 m/s. Also find out the volumetric flow rate and mass flow rate.
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Explain Buckingham π-theorem and Rayleigh’s method used in dimensional analysis.
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An oil of specific gravity 0.85 is flowing through a pipe of 5cm diameter at the rate of 3 lit/sec. Find the type of flow, if the viscosity for the oil is 3.8 poise.
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Find the loss of head due to friction in pipe of 1m diameter and 15 km long. The velocity of water in the pipe is 1m/sec. Take friction factor (f) = 0.005.
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Air enters a convergent-divergent nozzle at a temperature of 555.6 K and a pressure of 20 atm. The throat area is one-half that of the discharge of the divergent section. Assuming the Mach number in the throat is 0.8, what are the values of the following quantities at the throat: pressure, temperature, linear velocity, density and mass velocity? For air γ = 1.4 and M = 29.
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Derive an expression for velocity in nozzle for an isentropic flow.
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A partial oxidation is carried out by passing air with 1.2 mole % hydrocarbon through 40 mm tubes packed with 2 m of 3 by 3mm cylindrical catalyst pellets. The air enters at 350°C and 2 atm with a superficial velocity of 1 m/s. What is the pressure drop through the packed tubes? How much would the pressure drop be reduced by using 4 mm pellets? Assume ε = 0.40.
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What is fluidization? Explain about different types of fluidization and also give their applications in industry.
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A pitot static tube having a coefficient of 0.98 is placed at the centre of pipeline in which benzene is flowing. A manometer attached to the Pitot tube contains mercury and benzene and shows a reading of 10cm. Calculate the velocity at the centre line of the pipe. Specific gravity of benzene is 0.88.
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Explain the classification of flow measuring devices. Describe Rota meter with a neat figure.
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