HEAT TRANSFER QUIZ

Maximum heat transfer rate is obtained in __________ flow.

Transition region

Laminar

Creeping

Turbulent

TRUE ANSWER : ?
YOUR ANSWER : ?

A diathermaneous substance __________ the thermal radiation completely.

Transmits

None of these

Reflects

Absorbs

TRUE ANSWER : ?
YOUR ANSWER : ?

(NRe.NPr)(D/L) is called the __________ number

Stanton

None of these

Graetz

Peclet

TRUE ANSWER : ?
YOUR ANSWER : ?

Grashhoff number is given by

gD³.β.Δtρ²/μ²

gD2βΔtρ/μ²

gD³βΔtP²/μ

gD2βΔtP²μ

TRUE ANSWER : ?
YOUR ANSWER : ?

The Graetz number is concerned with the

heat transfer in laminar flow

mass transfer between a gas and a liquid

heat transfer in turbulent flow

absorption with chemical reaction

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following has maximum thermal conductivity?

Coal

Iron

Nitrogen

Tar

TRUE ANSWER : ?
YOUR ANSWER : ?

The heat flux in the nucleate boiling regimes is proportional to (where, ΔT = excess temperature)

(ΔT)³

(ΔT)⁴

(ΔT)²

√(ΔT)

TRUE ANSWER : ?
YOUR ANSWER : ?

The heat transfer co-efficient in film type condensation is __________ that for dropwise condensation.

Greater than

Is same as

Lower than

Half

TRUE ANSWER : ?
YOUR ANSWER : ?

Prandtl and Reynolds analogy are same, when Prandtl number is

0.5

> 2

1.5

1

TRUE ANSWER : ?
YOUR ANSWER : ?

The critical radius 'r' of insulation on a pipe is given by

r = k/h

r = k/2h

r = 2k/h

r = h/k

TRUE ANSWER : ?
YOUR ANSWER : ?

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