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March 2019

The overall heat transfer co-efficient for a shell and tube heat exchanger for clean surfaces is U0 = 400 W/m2.K. The fouling factor after one year of operation is found to be hd0 = 2000 W/m2.K. The overall heat transfer co-efficient at this time is _____________________?

Chemical Heat Transfer /
The overall heat transfer co-efficient for a shell and tube heat exchanger for clean surfaces is U0 = 400 W/m2.K. The fouling factor after one year of operation is found to be hd0 = 2000 W/m2.K. The overall heat transfer co-efficient at this time is _____________________?

A. 1200 W/m2.K
B. 894 W/m2.K
C. 333 W/m2.K
D. 287 W/m2.K

The overall heat transfer co-efficient for a shell and tube heat exchanger for clean surfaces is U0 = 400 W/m2.K. The fouling factor after one year of operation is found to be hd0 = 2000 W/m2.K. The overall heat transfer co-efficient at this time is _____________________? Read More »

Chemical Heat Transfer

In case of a super-cooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is ________________?

Chemical Heat Transfer /
In case of a super-cooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is ________________?

A. More
B. Less
C. Same
D. More or less; depends on the nature of solution

In case of a super-cooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is ________________? Read More »

Chemical Heat Transfer

Resistance to heat flow by conduction is proportional to (where, t & ρ are thickness & density of the material respectively and A = area normal to the direction of heat flow.) ?

Chemical Heat Transfer /
Resistance to heat flow by conduction is proportional to (where, t & ρ are thickness & density of the material respectively and A = area normal to the direction of heat flow.) ?

A. t
B. 1/ρ
C. 1/A
D. All A., B. & C.

Resistance to heat flow by conduction is proportional to (where, t & ρ are thickness & density of the material respectively and A = area normal to the direction of heat flow.) ? Read More »

Chemical Heat Transfer

Dittus-Boelter equation used for the determination of heat transfer co-efficient is valid ___________________?

Chemical Heat Transfer /
Dittus-Boelter equation used for the determination of heat transfer co-efficient is valid ___________________?

A. For fluids in laminar flow
B. For fluids in turbulent flow
C. When Grashoff number is very important
D. For liquid metals

Dittus-Boelter equation used for the determination of heat transfer co-efficient is valid ___________________? Read More »

Chemical Heat Transfer

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

Chemical Heat Transfer /
A multiple effect evaporator as compared to a single effect evaporator of the same capacity has _________________?

A. Lower heat transfer area
B. Lower steam economy
C. Higher steam economy
D. Higher solute concentration in the product

A multiple effect evaporator as compared to a single effect evaporator of the same capacity has _________________? Read More »

Chemical Heat Transfer