Ch 9

Question 1

Heat Transfer Process for Heat Exchanger

Answer 1

1. Convection from heat source to heat exchanger
2. Conduction through tube walls
3. Convection to carry energy away to heat sink

Question 2

Steady state heat transfer rate for heat exchanger is equal to heat generation rate of heat source.

Answer 2

Yep

Question 3

Heat transfer rate is directly proportional to:

Answer 3

1. Mass flow rate
2. Specific heat capacity of fluid
3. Differential temperature of fluid

Question 4

Average differential temperature for heat exchanger describes average temperature difference for the two fluids in the heat exchanger.

Answer 4

Yep

Question 5

When the cooling water inlet temperature changes what happens to the heat exchanger temperature?

Answer 5

It changes to maintain the differential temperatures constant.

Question 6

Fouling will affect the heat exchanger tubes and reduce the overall heat transfer coefficient U.

Answer 6

Yep

Question 7

If heat transfer coefficient decreases, the heat exchanger temperature will increase and operating temps for equipment will be higher.

Answer 7

Yep

Question 8

Air in heat exchangers lowers the overall heat transfer coefficient.

Answer 8

Yep