Which of the following statements are not true about fouling in a Heat Exchanger?

It decreases the heat transfer coefficient in both sides

Temperature of the hot fluid remains hot and the cold fluid remains cold

For the calculation of Dirty Overall Heat transfer coefficient UD, for given fouling factor Rf and Dirt Factor Rd, which one of the following expressions do we use?

( frac{1}{U_D} = frac{1}{U_C} + R_D )

( frac{1}{U_D} = frac{1}{U_C} + frac{1}{R_D} )

Which of the following methods can determine the fouling factor of a Heat Exchangers?

A dirty and a fully choked Heat Exchanger

A dirty and a clean Heat Exchanger

A dirty and a fully choked Heat Exchanger

Which one of the following cannot be determined by knowing fouling factors?

When the equipment will stop to work

Its value is zero for a new heat exchanger

Its value is infinity for an old heat exchanger

14 + Mcqs in Double Pipe Heat Exchangers Dirt Factor and Overall Heat Transfer Coefficients in Heat Transfer Operations Page 1 McqOptions

1.	Correctly select the plot of heat transfer coefficient vs the time of use of the equipment.
A.	<a href="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14a.png"><img alt="The plot of heat transfer coefficient vs the time of use of the equipment - option a" class="alignnone size-full wp-image-248104" height="404" sizes="(max-width: 559px) 100vw, 559px" src="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14a.png" srcset="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14a.png 559w, https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14a-300x217.png 300w" width="559"/></a>
B.	<a href="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14b.png"><img alt="The plot of heat transfer coefficient vs the time of use of the equipment - option b" class="alignnone size-full wp-image-248105" height="400" sizes="(max-width: 561px) 100vw, 561px" src="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14b.png" srcset="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14b.png 561w, https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14b-300x214.png 300w" width="561"/></a>
C.	<a href="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14c.png"><img alt="The plot of heat transfer coefficient vs the time of use of the equipment - option c" class="alignnone size-full wp-image-248106" height="399" sizes="(max-width: 563px) 100vw, 563px" src="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14c.png" srcset="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14c.png 563w, https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14c-300x213.png 300w" width="563"/></a>
D.	<a href="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14d.png"><img alt="The plot of heat transfer coefficient vs the time of use of the equipment - option d" class="alignnone size-full wp-image-248107" height="402" sizes="(max-width: 569px) 100vw, 569px" src="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14d.png" srcset="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14d.png 569w, https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14d-300x212.png 300w" width="569"/></a>
Answer» D. <a href="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14d.png"><img alt="The plot of heat transfer coefficient vs the time of use of the equipment - option d" class="alignnone size-full wp-image-248107" height="402" sizes="(max-width: 569px) 100vw, 569px" src="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14d.png" srcset="https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14d.png 569w, https://www.sanfoundry.com/wp-content/uploads/2019/10/heat-transfer-operations-questions-answers-dirt-factor-overall-heat-transfer-coefficients-q14d-300x212.png 300w" width="569"/></a>

Discussion

2.	Which of the following statements are not true about fouling in a Heat Exchanger?
A.	It decreases the heat transfer coefficient in both sides
B.	Temperature of the hot fluid remains hot and the cold fluid remains cold
C.	Pressure drop decreases
D.	Efficiency decreases
Answer» D. Efficiency decreases

Discussion

3.	Which one of the following fouling deposits on a heat exchanger cannot be removed by using wire brushes or high speed water jets?
A.	Chemical
B.	Deposition
C.	Biology
D.	Corrosion
Answer» E.

Discussion

4.	Nickel alloy based Heat exchangers are used to avoid _____ fouling.
A.	Chemical
B.	Deposition
C.	Biology
D.	Corrosion
Answer» E.

Discussion

5.	Which one of the following fouling phenomenon is under the control of the operator?
A.	Chemical
B.	Deposition
C.	Biology
D.	Corrosion
Answer» C. Biology

Discussion

6.	Algal deposits on the tube surfaces of the heat exchanger belong to which class of fouling?
A.	Chemical
B.	Deposition
C.	Biology
D.	Corrosion
Answer» D. Corrosion

Discussion

7.	The phenomenon of scaling on the surface of a Heat Exchanger due to the hardness of water where salts get deposited on the surface is an example of ____ fouling.
A.	Chemical
B.	Deposition
C.	Biology
D.	Corrosion
Answer» B. Deposition

Discussion

8.	Deposition fouling can be avoided or controlled by monitoring the flow velocity of the fluid so that sediments don t settle out.
A.	True
B.	False
Answer» B. False

Discussion

9.	For the calculation of Dirty Overall Heat transfer coefficient U_D, for given fouling factor R_f and Dirt Factor R_d, which one of the following expressions do we use?
A.	( frac{1}{U_D} = frac{1}{U_C} + R_D )
B.	( frac{1}{U_D} = frac{1}{U_C} + frac{1}{R_D} )
C.	U<sub>D</sub> = U<sub>C</sub> + R<sub>D</sub>
D.	U<sub>D</sub> = (U_C+ frac{1}{R_D} )
Answer» C. U<sub>D</sub> = U<sub>C</sub> + R<sub>D</sub>

Discussion

10.	Which one of the following is not a collective class of fouling?
A.	Biological fouling
B.	Deposition Fouling
C.	Chemical Fouling
D.	Iron fouling
Answer» E.

Discussion

11.	How many types of readily identifiable Fouling exist?
A.	1
B.	2
C.	3
D.	4
Answer» E.

Discussion

12.	Which of the following methods can determine the fouling factor of a Heat Exchangers?
A.	A dirty Heat Exchanger
B.	A clean Heat Exchanger
C.	A dirty and a clean Heat Exchanger
D.	A dirty and a fully choked Heat Exchanger
Answer» D. A dirty and a fully choked Heat Exchanger

Discussion

13.	Which one of the following cannot be determined by knowing fouling factors?
A.	When to clean the equipment
B.	When the equipment will stop to work
C.	Its value is zero for a new heat exchanger
D.	Its value is infinity for an old heat exchanger
Answer» E.

Discussion

14.	Fouling factors increase the overall heat transfer conductance and hence decrease the overall heat transfer coefficient.
A.	True
B.	False
Answer» C.

Discussion

Explore topic-wise MCQs in Heat Transfer Operations.

Correctly select the plot of heat transfer coefficient vs the time of use of the equipment.

Which of the following statements are not true about fouling in a Heat Exchanger?

Which one of the following fouling deposits on a heat exchanger cannot be removed by using wire brushes or high speed water jets?

Nickel alloy based Heat exchangers are used to avoid _____ fouling.

Which one of the following fouling phenomenon is under the control of the operator?

Algal deposits on the tube surfaces of the heat exchanger belong to which class of fouling?

The phenomenon of scaling on the surface of a Heat Exchanger due to the hardness of water where salts get deposited on the surface is an example of ____ fouling.

Deposition fouling can be avoided or controlled by monitoring the flow velocity of the fluid so that sediments don t settle out.

For the calculation of Dirty Overall Heat transfer coefficient UD, for given fouling factor Rf and Dirt Factor Rd, which one of the following expressions do we use?

Which one of the following is not a collective class of fouling?

How many types of readily identifiable Fouling exist?

Which of the following methods can determine the fouling factor of a Heat Exchangers?

Which one of the following cannot be determined by knowing fouling factors?

Fouling factors increase the overall heat transfer conductance and hence decrease the overall heat transfer coefficient.

For the calculation of Dirty Overall Heat transfer coefficient U_D, for given fouling factor R_f and Dirt Factor R_d, which one of the following expressions do we use?