GATE CH Fluid Mechanics and Mechanical Operations PYQs & Answers — Page 6

Questions 51–60 of 77. Imported answers require independent review unless marked reviewed.

A student performs a flow experiment with Bingham Plastic under fully developed laminar flow conditions in a tube of radius 0.01 m with a pressure drop (

) of 10 kPa over tube length (

) of 1.0 m. The velocity profile is flat for

and parabolic for

, as shown in the figure.

Diagram for Chemical Engineering question 36

Consider

and

as the radial and axial directions, and the shear stress is finite as

approaches zero. A force balance results in the following equation

where

is the shear stress. If

is 0.001 m, then the magnitude of yield stress for this Bingham Plastic (in Pa) is

Your answerChoose one option.

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A U-tube manometer contains two manometric fluids of densities 100 kg m

and 600 kg m

. When both the limbs are open to atmosphere, the difference between the two levels is 10 cm at equilibrium, as shown in the figure.

The rest of the manometer is filled with air of negligible density. The acceleration due to gravity is 9.81 m s

and the atmospheric pressure is 100 kPa. How much absolute pressure (in kPa) has to be applied on the limb ‘P’ to raise fluid in the limb ‘Q’ by another 20 cm?

Diagram for Chemical Engineering question 38

Your answerChoose one option.

100.175

103.924

547.231

833.206

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Liquid water is pumped at a volumetric flow rate of 0.02 m

from Tank I to Tank II, as shown in the figure.

Diagram for Chemical Engineering question 43

Both the tanks are open to the atmosphere. The total frictional head loss for the pipe system is 1.0 m of water.

In addition, use the following data and assumptions:

Density of water is 1000 kg m

Acceleration due to gravity is 9.81 m s

Efficiency of the pump is 100%

The liquid surfaces in the tanks have negligible velocities

The power supplied (in W) by the pump to lift the water is ________ (round off to 1 decimal place).

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A vertically held packed bed has a height of 1 m, and a void fraction of 0.1, when there is no flow through the bed. The incipient (minimum) fluidization is set in by injection of a fluid of density 1 kg m

. The particle density (

) of the solids is 3000 kg m

. Acceleration due to gravity is 9.81 m s

. The pressure drop (in Pa) across the height of the bed is ________ (round off to nearest integer).

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For a fully-developed turbulent hydrodynamic boundary layer for flow past a flat plate, the thickness of the boundary layer increases with distance

from the leading edge of the plate, along the free-stream flow direction, as

Your answerChoose one option.

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Consider a cylinder (diameter

and length

), a sphere (diameter

) and a cube (side length

). Which of the following statements concerning the sphericity (

) of the above objects is true:

Your answerChoose one option.

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Prandtl number signifies the ratio of

Your answerChoose one option.

Momentum Diffusivity / Thermal Diffusivity

Mass Diffusivity / Thermal Diffusivity

Thermal Diffusivity / Momentum Diffusivity

Thermal Diffusivity / Mass Diffusivity

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For a hydraulic lift with dimensions shown in figure, assuming

, the maximum diameter

(in m) that lifts a vehicle of mass 1000 kg using a force of 100 N is ______ (rounded off to two decimal places).

Diagram for Chemical Engineering question 23

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An incompressible Newtonian fluid flows in a pipe of diameter

at volumetric flow rate

. Fluid with same properties flows in another pipe of diameter

at the same flow rate

. The transition length required for achieving fully-developed flow is

for the tube of diameter

, while it is

for the tube of diameter

. Assuming steady laminar flow in both cases, the ratio

is:

Your answerChoose one option.

1/4

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A disk turbine is used to stir a liquid in a baffled tank. To design the agitator, experiments are performed in a lab-scale model with a turbine diameter of 0.05 m and a turbine impeller speed of 600 rpm. The liquid viscosity is 0.01 Pa s while the liquid density is 1000 kg/m

. The actual application has a turbine diameter of 0.5 m, an impeller speed of 600 rpm, a liquid viscosity of 0.1 Pa s and a liquid density of 1000 kg/m

. The effect of gravity is negligible. If the power required in the lab-scale model is

and the estimated power for the actual application is

, then the ratio

Your answerChoose one option.

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GATE CH Fluid Mechanics and Mechanical Operations PYQs

Question 36

Question 38

Question 43

Question 46

Question 6

Question 7

Question 8

Question 23

Question 28

Question 29