Heat dissipation in cooling towers is mainly by

Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the

A

Packing may be crushed due to thermal expansion/contraction of the components of the equipments

B

Pressure drop in the equipment will be very high

C

Viscosity variation of the fluids may cause channeling/flooding

D

None of these

The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives

A

Low pressure drop and high hold up

B

High pressure drop and low hold up

C

Low pressure drop and low hold up

D

High pressure drop and high hold up

In case of cooling towers, the ratio of the rates of heat and mass transfer is indicated by the __________ number.

A

Lewis

B

Grashoff

C

Sherwood

D

None of these

Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan

A

With greater number of blades

B

Of increased diameter

C

Both A & B

D

Neither A nor B

Which one of the following equations most directly determines the power dissipation of a resistance when you know the power dissipation of a resistance when you know the voltage drop and current?

A

P = IE

B

P = E²/R

C

P = I²R

D

I = P/E

E

None of the above

Water entrained by circulating air in cooling towers is termed as

A

Drift

B

Blow down

C

Vapor load

D

None of these

The heated parts of an electrical machine dissipate heat into their surroundings by which of the followingmodes of heat dissipation ?

A

Conduction

B

Convection

C

Radiation

D

All of the above

The mcrease in heat dissipation by air blasts is due to increase in

A

conduction

B

convection

C

radiation

D

any ofthe above

________ cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall

A

Direct

B

Indirect

C

Conventional

D

Any of the above

The cooling effect in a cooling tower can not be increased by

A

Increasing the air velocity over the wet surfaces

B

Reducing the humidity of entering air

C

Lowering the barometric pressure

D

None of these

Heat dissipation in cooling towers is mainly by

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