Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech II CHEMICAL ENGINEERING FLUID MECHANICS Previous Question Paper (December - 2017 - 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
Differentiate Laminar and Turbulent Flows.
Answer
In Laminar flow, fluid particles move in smooth, parallel layers (laminae) with no macroscopic mixing, typically occurring at low Reynolds numbers. In Turbulent flow, fluid motion is characterized by chaotic, irregular fluctuations and eddies, leading to significant mixing and momentum transfer, typically occurring at high Reynolds numbers.
Explain the terms Reynolds shear stress.
Answer
Reynolds shear stress, also known as turbulent shear stress, arises in turbulent flow due to the fluctuating velocity components of the fluid. It represents the transport of momentum caused by the turbulent eddies and is defined as the negative of the time-average of the product of the fluctuating velocity components in the flow direction and the direction normal to it, multiplied by the fluid density:
Write Bernoulli’s equation and explain different term present in the equation.
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What is Rayleigh’s method?
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What is Mach number?
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Write about Isothermal Frictional flow.
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Distinguish between Free Settling and Hindered settling.
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Write advantages, disadvantages and applications of fluidization.
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Write the difference between full bore meters and insertion meters.
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Explain NPSH.
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Part B
Oil of density 900 kg/m3 flows through a pipe line of 150mm diameter at section A and enters in to another pipe of 300mm diameter at section B. Section B is 4.5 m higher than section A. If gauge pressures at A and B are 300 and 600 kN/m2 respectively determine energy loss when pipe carries a discharge of 0.110 m3/s.
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A pressure measuring instrument reads 20 in of Hg when the atmospheric pressure is 30 in. Hg. Assuming the density of mercury to be 13,600 kg/m3, determine the absolute pressure in Pascal.
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Write momentum balance for a fluid flow in a pipe and explain the different forces acting.
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It is planned to install a steel pipe line with an inside diameter of 202 mm to transport 3800 m3 of oil per day. The pipe line is to be 32 km long and the delivery end is to be 30 m higher than the intake. If the frictional pressure drop in the pipe line is estimated to be 5.3 MPa and the overall efficiency of the pump motor set is 60%, calculate the power requirement of the pump-motor set in kW. The density and viscosity of the oil are 897 kg/m3 and 50 mPaS, respectively.
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The pressure drop of a fluid flowing through a pipe depends on the length of the pipe L, density, viscosity, diameter of the pipe d, characteristic length l and velocity V. By using Rayleigh method and Buckingham method find out the various dimensionless groups in to which these variables can be reduced.
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Discuss in detail about the isentropic flow through nozzles and its related equations.
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Derive an expression for critical pressure ratio for the isentropic flow of an ideal gas through a nozzle.
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Argon gas (Molecular weight =40) flows adiabatically through a pipe of 26.5 mm internal diameter. The gas enters the pipe at a pressure of 7 atm, temperature of 100oC and a velocity of 30 m/s. Take friction factor as 0.004, γ as 1.67 and R as 208 J/kg K. What is the pressure and stagnation temperature at the end of the maximum length?
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Derive Kozney-Karman equation for a packed bed by stating the necessary assumptions.
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Calculate the pressure drop of air flowing at 30oC and 1 atm pressure through a bed of 1.25 cm diameter spheres, at a rate of 60 kg/min. The bed is 125 cm diameter and 250 cm height. The porosity of the bed is 0.38. The viscosity of air is 0.0182 cP and the density is 0.001156 gm/cc.
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What is fluidization? Derive an expression to calculate minimum fluidization velocity.
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Explain in detail about Particulate fluidization, Bubbling fluidization and Slugging with the help of a neat schematic.
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Discuss in detail about the working principle of Venturimeter.
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A pipe line of 18 cm diameter has a venture meter whose throat is of 6 cm diameter. The coefficient of discharge of the venturi is 0.98 and the difference in head between the entrance and throat is read as 12 cm in U-tube mercury manometer. Find the volumetric flow rate of water through the pipe line.
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What size of orifice would give a pressure difference of 41 cm of water column for the flow of liquid styrene of specific gravity 0.9 at 0.055 m3/s in a 250 mm diameter pipe? Assume orifice coefficient to be 0.62?
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Explain different types of reciprocating pumps.
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