1. What are the examples of indirect heat exchangers?
a) Shell and tube Heat exchanger, Plate heat exchangers
b) Steam injectors, plate heat exchangers
c) Cooling towers, Plate heat exchangers
d) Steam injectors, cooling towers
Discussion
Explanation: Indirect heat exchanger, the two fluids can transfer the heat where one fluid flows inside the tubes and other fluid flows over the tubes. Shell and tube Heat exchanger, Plate heat exchangers are the examples of indirect heat exchangers. Steam injectors, cooling towers are the examples of direct heat exchangers.
2. What are the examples of direct heat exchangers?
a) Shell and tube Heat exchanger, Plate heat exchangers
b) Steam injectors, plate heat exchangers
c) Cooling towers, Plate heat exchangers
d) Steam injectors, cooling towers
Discussion
Explanation: In direct heat exchangers, there is a direct contact between the two immiscible fluids for transferring the heat. Cooling towers, jet condensers, steam injectors are the examples of direct heat exchangers.
3. What type of heat exchanger is used in cryogenic applications?
a) Shell and tube Heat exchanger
b) Plate heat exchanger
c) Finned tube heat exchanger
d) Plate fin heat exchanger
Discussion
Explanation: Plate fin heat exchangeris used in cryogenic applications. They use corrugated fins which are separated by flat plates. These are used in gas-to-gas applications at where it has low pressures and temperatures not above 800°C.
4. Which of the following statements about Printed circuit heat exchanger are correct?
Statement 1: Printed circuit heat exchanger is an example for direct heat exchanger.
Statement 2: It has high heat transfer surface area per unit volume of the exchanger.
a) True, False
b) True, True
c) False, True
d) False, False
Discussion
Explanation: Printed circuit heat exchanger is an example for indirect heat exchanger. It can be used as alternatives to shell and tube heat exchanger. It has high heat transfer surface area per unit volume of the exchanger. It also reduces the energy requirement. But it is expensive than shell and tube units and the fluid needs to be extremely clean or else blockages can occur due to the fine channels. Therefore the fluids are filtered before the feeding into inlet pipe.
5. _____________ consists of a single tube mounted inside another tube.
a) Shell and tube Heat exchanger
b) Plate heat exchanger
c) Double tube heat exchanger
d) Plate fin heat exchanger
Discussion
Explanation: Double pipe heat exchanger contains of two concentric pipes of different diameters. One pipe is for cold fluid and the other one is for hot fluid.The fluid can flowin co-current direction or counter current direction.
6. _________ is used as rear header in a U-Tube heat exchanger.
a) M type
b) A type
c) U type
d) D type
Discussion
Explanation: M typeis used as rear header in a U-Tube heat exchanger. The U-tubes permit unlimited thermal extension, the bundles of the tubes can be removed to clean. But internal cleaning of the tubes are difficult due to the small diameter, therefore the fluids are filtered before entering into the feed pipe.
7. __________is used for horizontal thermosyphon reboilers.
a) G type
b) A type
c) C type
d) Y type
Discussion
Explanation: G typefront header is used for horizontal thermosyphon reboilers. A-Type front header is used for easy cleaning or repair of the tubes without having to disturb the pipe work. C type header is for high pressure applications. Y-Type header used as a front or rear header and is used when the exchanger is in pipe line.
8. __________ uses an intermediate fluid or solid store to hold heat.
a) Shell and tube Heat exchanger
b) Plate heat exchanger
c) Double tube heat exchanger
d) Adiabatic wheel heat exchanger
Discussion
Explanation: Adiabatic wheel heat exchangercontains a wheel and uses an intermediate fluid to hold heatand then the heat is transferred to the other side of the heat exchanger. It is used in transfer of heat between gases efficiently which is not easily possible in other heat exchanger.
9. What is heat economizing?
a) The total cost of the heat exchanger and its maintenance cost
b) Interchange heat among the hot and cold fluids to conserve heat energy.
c) The capital cost of the heat exchanger unit
d) Amount of heat produced per day
Discussion
Explanation: Heat economizing can be defined as the Interchange heat among the hot and cold fluids to conserve heat energy. The heat from the hot liquid is transferred to the cool liquid thus reducing the overall cost of the heating mechanism. This is especially achieved when the arrangement is in counter flow mechanism.
10. Who invented the heat exchanger?
a) Dr Richard Seligman
b) George Babcock
c) George Brayton
d) Benjamin Franklin
Discussion
Explanation: Dr Richard Seligman invented heat exchanger. George Babcock invented boiler. George Brayton invented engine. Benjamin Franklin invented electricity.