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For flow over a flat plate, the ratio of thermal boundary layer thickness, ‘xt’ and hydrodynamic boundary layer thickness ‘x’ is equal to (where, NPr = Prandtl number)

CHEMICAL ENGINEERING, Heat Transfer /
Question: For flow over a flat plate, the ratio of thermal boundary layer thickness, ‘xt’ and hydrodynamic boundary layer thickness ‘x’ is equal to (where, NPr = Prandtl number)
[A].

NPr

[B].

NPr1/3

[C].

NPr-1

[D].

NPr-1/3

Answer: Option B

Explanation:

No answer description available for this question.

For flow over a flat plate, the ratio of thermal boundary layer thickness, ‘xt’ and hydrodynamic boundary layer thickness ‘x’ is equal to (where, NPr = Prandtl number) Read More »

CHEMICAL ENGINEERING, Heat Transfer

Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the

CHEMICAL ENGINEERING, Heat Transfer /
Question: Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the
[A].

existence of thermal boundary layer.

[B].

temperature gradient produced due to density difference

[C].

buoyancy of the bubbles produced at active nucleation site.

[D].

none of these.

Answer: Option D

Explanation:

No answer description available for this question.

Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the Read More »

CHEMICAL ENGINEERING, Heat Transfer

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the

CHEMICAL ENGINEERING, Heat Transfer /
Question: Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
[A].

surrounding temperature.

[B].

average temperature of the fin.

[C].

temperature of the fin end.

[D].

constant temperature equal to that of the base

Answer: Option D

Explanation:

No answer description available for this question.

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the Read More »

CHEMICAL ENGINEERING, Heat Transfer

In Biot number, the characteristic length used is the ratio of the __________ of the solid.

CHEMICAL ENGINEERING, Heat Transfer /
Question: In Biot number, the characteristic length used is the ratio of the __________ of the solid.
[A].

volume to surface area

[B].

perimeter to surface area

[C].

surface area to volume

[D].

surface area to perimeter

Answer: Option A

Explanation:

No answer description available for this question.

In Biot number, the characteristic length used is the ratio of the __________ of the solid. Read More »

CHEMICAL ENGINEERING, Heat Transfer

A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides

CHEMICAL ENGINEERING, Heat Transfer /
Question: A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides
[A].

higher economy

[B].

lower capacity

[C].

both (a) & (b)

[D].

lower economy

Answer: Option A

Explanation:

No answer description available for this question.

A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides Read More »

CHEMICAL ENGINEERING, Heat Transfer

With increase in temperature, the thermal conductivity of fresh lubricating oil

CHEMICAL ENGINEERING, Heat Transfer /
Question: With increase in temperature, the thermal conductivity of fresh lubricating oil
[A].

increases

[B].

decreases

[C].

remains unchanged

[D].

may increase or decrease; depends on its composition

Answer: Option B

Explanation:

No answer description available for this question.

With increase in temperature, the thermal conductivity of fresh lubricating oil Read More »

CHEMICAL ENGINEERING, Heat Transfer

If air (a non-condensing gas) is present in a condensing vapor stream, it will __________ the condensation rate of vapor.

CHEMICAL ENGINEERING, Heat Transfer /
Question: If air (a non-condensing gas) is present in a condensing vapor stream, it will __________ the condensation rate of vapor.
[A].

increase

[B].

decrease

[C].

not affect

[D].

increase the condensing film co-efficient as well as

Answer: Option B

Explanation:

No answer description available for this question.

If air (a non-condensing gas) is present in a condensing vapor stream, it will __________ the condensation rate of vapor. Read More »

CHEMICAL ENGINEERING, Heat Transfer