University of Baby on Faculty of Engineering-AIMusyab Automobile Eng. Dep. Year: 2022-2023. 1 Course, 1" Attempt Stage 3 Subject Heat Transfer I Date: 2023 01 23- Monday Time: 3 Hours Notes: Q1: • • Answer four questions only Use Troles and Appendices A) A flat wall is exposed to an environmental temperature of 38°C. The wall is covered with a layer of insulation 2.5 cm thick whose thermal conductivity is 1.4 W/m. C, and the temperature of the wall on the inside of the insulation is 315°C. The wall loses heat to the environment by convection. Compute the value of the convection heat-transfer coefficient that must be maintained on the outer surface of the insulation to ensure that the outer-surface temperature does not exceed 41°C. B) A vertical square plate, 30 cm on a side, is maintained at 50°C and exposed to room air at 20°C. The surface emissivity is 0.8. Calculate the total heat lost by both sides of the plate. (12.5 M) Q2: An aluminum fin 1.5 mm thick is placed on a circular tube with 2.7cm OD. The fin is 6 mm long. The tube wall is maintained at 150°C, the environment temperature is 15°C, and the convection heat-transfer coefficient is 20 W/m². 'C. Calculate the heat lost by the fin? Q3: Write the nodal equation for nodes 1 through 12 shown in Figure (1). (12.5 M) Examiner: sarmanan Q. Ibrahim S22 Insulated- 5 6 1 50 C A Jo Wm C 100°C 10 11 12 150 C TIS C Figure (1) (12.5 M) Head of Department: Dr. Dhyai Hassan Jawad
University of Baby on Faculty of Engineering-AIMusyab Automobile Eng. Dep. Year: 2022-2023. 1 Course, 1" Attempt Stage 3 Subject Heat Transfer I Date: 2023 01 23- Monday Time: 3 Hours Notes: Q1: • • Answer four questions only Use Troles and Appendices A) A flat wall is exposed to an environmental temperature of 38°C. The wall is covered with a layer of insulation 2.5 cm thick whose thermal conductivity is 1.4 W/m. C, and the temperature of the wall on the inside of the insulation is 315°C. The wall loses heat to the environment by convection. Compute the value of the convection heat-transfer coefficient that must be maintained on the outer surface of the insulation to ensure that the outer-surface temperature does not exceed 41°C. B) A vertical square plate, 30 cm on a side, is maintained at 50°C and exposed to room air at 20°C. The surface emissivity is 0.8. Calculate the total heat lost by both sides of the plate. (12.5 M) Q2: An aluminum fin 1.5 mm thick is placed on a circular tube with 2.7cm OD. The fin is 6 mm long. The tube wall is maintained at 150°C, the environment temperature is 15°C, and the convection heat-transfer coefficient is 20 W/m². 'C. Calculate the heat lost by the fin? Q3: Write the nodal equation for nodes 1 through 12 shown in Figure (1). (12.5 M) Examiner: sarmanan Q. Ibrahim S22 Insulated- 5 6 1 50 C A Jo Wm C 100°C 10 11 12 150 C TIS C Figure (1) (12.5 M) Head of Department: Dr. Dhyai Hassan Jawad
Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
8th Edition
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
Publisher:Kreith, Frank; Manglik, Raj M.
Chapter1: Basic Modes Of Heat Transfer
Section: Chapter Questions
Problem 1.77P: 1.77 Explain each in your own words. (a) What is the mode of heat transfer through a large steel...
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Transcribed Image Text:University of Baby on
Faculty of Engineering-AIMusyab
Automobile Eng. Dep.
Year: 2022-2023.
1 Course, 1" Attempt
Stage 3
Subject Heat Transfer I
Date: 2023 01 23- Monday
Time: 3 Hours
Notes:
Q1:
•
•
Answer four questions only
Use Troles and Appendices
A) A flat wall is exposed to an environmental temperature of 38°C. The wall is covered
with a layer of insulation 2.5 cm thick whose thermal conductivity is 1.4 W/m. C,
and the temperature of the wall on the inside of the insulation is 315°C. The wall
loses heat to the environment by convection. Compute the value of the convection
heat-transfer coefficient that must be maintained on the outer surface of the
insulation to ensure that the outer-surface temperature does not exceed 41°C.
B) A vertical square plate, 30 cm on a side, is maintained at 50°C and exposed to room
air at 20°C. The surface emissivity is 0.8. Calculate the total heat lost by both sides
of the plate.
(12.5 M)
Q2: An aluminum fin 1.5 mm thick is placed on a circular tube with 2.7cm OD. The fin is
6 mm long. The tube wall is maintained at 150°C, the environment temperature is 15°C, and
the convection heat-transfer coefficient is 20 W/m². 'C. Calculate the heat lost by the fin?
Q3: Write the nodal equation for nodes 1 through 12 shown in Figure (1).
(12.5 M)
Examiner:
sarmanan Q. Ibrahim
S22
Insulated-
5
6
1
50 C
A
Jo Wm C
100°C
10
11
12
150 C
TIS C
Figure (1)
(12.5 M)
Head of Department:
Dr. Dhyai Hassan Jawad
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