A test is performed to determine the overall heat transfer coefficient of a shell-and-tube oil-to- water heat exchanger with 24 tubes of internal diameter 0.012 m and length 2 m (this is not the total L and D) in a single shell. Cold water (cp=4.180 kJ/kg° C) enters the tubes at 20° C and exits at 55° C at a rate of 3 kg/s. Oil cools the shell from 120° C to 45° C (cp= 2.150 kJ/kg°C). Because the heat exchanger is well-insulated, heat loss to the surroundings is negligible. The kinetic and potential energies of a fluid stream change insignificantly. Correction factor: F = 0.7 a) Determine the overall heat transfer coefficient U (kW/m². °C) of this heat exchanger based on the inner surface area of the tubes (use LMTD method). IkJ/s=1kW b) What is the primary reason for using many tube passes?
A test is performed to determine the overall heat transfer coefficient of a shell-and-tube oil-to- water heat exchanger with 24 tubes of internal diameter 0.012 m and length 2 m (this is not the total L and D) in a single shell. Cold water (cp=4.180 kJ/kg° C) enters the tubes at 20° C and exits at 55° C at a rate of 3 kg/s. Oil cools the shell from 120° C to 45° C (cp= 2.150 kJ/kg°C). Because the heat exchanger is well-insulated, heat loss to the surroundings is negligible. The kinetic and potential energies of a fluid stream change insignificantly. Correction factor: F = 0.7 a) Determine the overall heat transfer coefficient U (kW/m². °C) of this heat exchanger based on the inner surface area of the tubes (use LMTD method). IkJ/s=1kW b) What is the primary reason for using many tube passes?
Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
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Heat Exchangers
Heat exchangers are the types of equipment that are primarily employed to transfer the thermal energy from one fluid to another, provided that one of the fluids should be at a higher thermal energy content than the other fluid.
Heat Exchanger
The heat exchanger is a combination of two words ''Heat'' and ''Exchanger''. It is a mechanical device that is used to exchange heat energy between two fluids.
Question
![A test is performed to determine the overall heat transfer coefficient of a shell-and-tube oil-to-water heat exchanger with 24 tubes of internal diameter 0.012 m and length 2 m (this is not the total L and D) in a single shell. Cold water (\(c_p = 4.180 \, \text{kJ/kg}^\circ \text{C}\)) enters the tubes at 20°C and exits at 55°C at a rate of 3 kg/s. Oil cools the shell from 120°C to 45°C (\(c_p = 2.150 \, \text{kJ/kg}^\circ \text{C}\)). Because the heat exchanger is well-insulated, heat loss to the surroundings is negligible. The kinetic and potential energies of a fluid stream change insignificantly. Correction factor: F = 0.7
a) Determine the overall heat transfer coefficient \(U \, (\text{kW/m}^2\cdot \text{°C})\) of this heat exchanger based on the inner surface area of the tubes (use LMTD method). \[1 \, \text{kJ/s} = 1 \, \text{kW}\]
b) What is the primary reason for using many tube passes?](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F95bcd5c9-4876-40cc-b5a4-4a5eba3df938%2Fc3c8be33-e2ce-43d6-8d60-62b0fbae7f4c%2F2qo4e9_processed.jpeg&w=3840&q=75)
Transcribed Image Text:A test is performed to determine the overall heat transfer coefficient of a shell-and-tube oil-to-water heat exchanger with 24 tubes of internal diameter 0.012 m and length 2 m (this is not the total L and D) in a single shell. Cold water (\(c_p = 4.180 \, \text{kJ/kg}^\circ \text{C}\)) enters the tubes at 20°C and exits at 55°C at a rate of 3 kg/s. Oil cools the shell from 120°C to 45°C (\(c_p = 2.150 \, \text{kJ/kg}^\circ \text{C}\)). Because the heat exchanger is well-insulated, heat loss to the surroundings is negligible. The kinetic and potential energies of a fluid stream change insignificantly. Correction factor: F = 0.7
a) Determine the overall heat transfer coefficient \(U \, (\text{kW/m}^2\cdot \text{°C})\) of this heat exchanger based on the inner surface area of the tubes (use LMTD method). \[1 \, \text{kJ/s} = 1 \, \text{kW}\]
b) What is the primary reason for using many tube passes?
Transcribed Image Text:**Heat Exchanger Diagram**
The image depicts a heat exchanger where oil and water are used as the working fluids. The setup consists of 24 tubes designed for optimal heat transfer between the fluids.
- **Oil Flow:**
- Inlet Temperature: 120°C
- Outlet Temperature: 55°C
- **Water Flow:**
- Inlet Temperature: 20°C
- Outlet Temperature: 45°C
- Flow Rate: 3 kg/s
**Explanation:**
The diagram illustrates the flow process within the heat exchanger. The oil enters at a higher temperature of 120°C and exits at 55°C after transferring heat to the water. Conversely, the water enters at 20°C and absorbs heat, raising its temperature to 45°C, with a flow rate of 3 kg/s. The system is designed to efficiently balance the heat exchange, represented by the parallel arrangement of 24 tubes.
Expert Solution
Step 1
To Find :
The overall heat transfer coefficient .
Given :
The internal diameter is
The number of tubes is
The lenght is
The specific heat of cold water is
The inlet temperature is
The exit temperature is
The mass flow rate is
The inlet temperature of oil is
The exit temperature of oil is
The specific heat of oil is
The correction factor is
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