HEAT TRANSFER QUIZ

Baffles are provided in heat exchangers to increase the

Heat transfer area

Heat transfer rate

Fouling factor

Heat transfer co-efficient

TRUE ANSWER : ?
YOUR ANSWER : ?

In the equation Q = UAΔt; Δt is

Geometric mean temperature difference

Logarithmic mean temperature difference

The difference of average bulk temperatures of hot and cold fluids

Arithmetic mean temperature difference

TRUE ANSWER : ?
YOUR ANSWER : ?

A multiple effect evaporator as compared to a single effect evaporator of the same capacity has

Higher solute concentration in the product

Higher steam economy

Lower heat transfer area

Lower steam economy

TRUE ANSWER : ?
YOUR ANSWER : ?

For __________ Prandtl number values, the heat conduction will be negligible in the buffer zone.

No

Extremely low

Low

High

TRUE ANSWER : ?
YOUR ANSWER : ?

Choose the correct equation.

Nu = (Re)(Pr)

Nu = (Re) (Pr) (Gz)

Nu = (Re) (Pr) (St)

Nu = (Pr)(St)

TRUE ANSWER : ?
YOUR ANSWER : ?

For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it

Increases the overall heat transfer coefficient

None of these

Decreases the outlet temperature of cooling medium

Decreases the pressure drop

TRUE ANSWER : ?
YOUR ANSWER : ?

Heat flux is the time rate of heat transfer per unit

area

none of the listed here

length

volume

TRUE ANSWER : ?
YOUR ANSWER : ?

The ratio of the total emissive power to the absorptivity for all bodies is same at ther-mal equilibrium. This is __________ law.

Kirchoffs

Wien's displacement

Planck's

Stefan-Boltzman

TRUE ANSWER : ?
YOUR ANSWER : ?

Which area is used in case of heat flow by conduction through a cylinder ?

Geometric mean area

Logarithmic mean area

None of the listed here

Arithmetic mean area

TRUE ANSWER : ?
YOUR ANSWER : ?

With increase in temperature, the thermal conductivity of most liquids

First increases upto a certain temperature and then becomes constant

Remains same

Decreases

Increases

TRUE ANSWER : ?
YOUR ANSWER : ?

↑