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Questions and Answers
What is the major mode of heat transfer in a double pipe heat exchanger?
What is the major mode of heat transfer in a double pipe heat exchanger?
When is a double pipe heat exchanger commonly used?
When is a double pipe heat exchanger commonly used?
What type of flow arrangement is characterized by hot and cold fluids entering at opposite ends of a heat exchanger?
What type of flow arrangement is characterized by hot and cold fluids entering at opposite ends of a heat exchanger?
What is the purpose of logarithmic mean temperature difference in a heat exchanger?
What is the purpose of logarithmic mean temperature difference in a heat exchanger?
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What is the definition of the heat transfer coefficient?
What is the definition of the heat transfer coefficient?
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Why is counter-flow direction preferred over parallel flow in a double pipe heat exchanger?
Why is counter-flow direction preferred over parallel flow in a double pipe heat exchanger?
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What happens when the logarithmic mean temperature difference is zero?
What happens when the logarithmic mean temperature difference is zero?
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Which flow arrangement is characterized by both hot and cold fluids entering and leaving the heat exchanger at the same end?
Which flow arrangement is characterized by both hot and cold fluids entering and leaving the heat exchanger at the same end?
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Which of the following statements accurately describes the heat transfer coefficient on the gas side of a double pipe heat exchanger?
Which of the following statements accurately describes the heat transfer coefficient on the gas side of a double pipe heat exchanger?
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What is the primary reason for using extended fins on the gas side of a double pipe heat exchanger?
What is the primary reason for using extended fins on the gas side of a double pipe heat exchanger?
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What is the relationship between the logarithmic mean temperature difference (LMTD) and the heat transfer rate in a double pipe heat exchanger?
What is the relationship between the logarithmic mean temperature difference (LMTD) and the heat transfer rate in a double pipe heat exchanger?
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Which of the following scenarios would result in a zero LMTD in a double pipe heat exchanger?
Which of the following scenarios would result in a zero LMTD in a double pipe heat exchanger?
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What is the primary function of the separating wall in a double pipe heat exchanger?
What is the primary function of the separating wall in a double pipe heat exchanger?
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In a double pipe heat exchanger, what type of heat transfer occurs between the fluid and the wall of the pipe?
In a double pipe heat exchanger, what type of heat transfer occurs between the fluid and the wall of the pipe?
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What is the main difference between co-current and counter-current flow in a double pipe heat exchanger?
What is the main difference between co-current and counter-current flow in a double pipe heat exchanger?
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Which of the following is NOT a benefit of using a double pipe heat exchanger?
Which of the following is NOT a benefit of using a double pipe heat exchanger?
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Study Notes
Heat Transfer in Double Pipe Heat Exchangers
- Major mean of heat transfer in a double pipe heat exchanger is convection and conduction.
- Double pipe heat exchangers are used when heat transfer area required is very low.
Flow Arrangements in Heat Exchangers
- Hot and cold fluids enter at the same end of a heat exchanger, which is the definition of parallel-flow.
- In co-current flow, both hot and cold streams enter the heat exchanger at one end, and leave at the opposite end.
- In counter-current flow, the streams enter at opposite ends of the heat exchanger.
Logarithmic Mean Temperature Difference (LMTD)
- LMTD is used to determine the temperature driving force for heat transfer in flow systems.
- When LMTD is zero, no further heat transfer is possible.
Heat Transfer Coefficient
- Heat transfer coefficient is defined as heat transferred per unit area per kelvin.
Convection and Conduction in Double Pipe Heat Exchangers
- Convection occurs when fluid is in a constant uniform motion inside the pipes, which increases the overall bulk temperature of the fluid.
- Conduction occurs when the separating wall carries heat from the hot fluid to the cold fluid through conduction.
Advantages of Counter-Flow Direction
- Counter-flow direction is better for the application of constant wall temperature in double pipe heat exchanger compared to co-current flow direction, as it experiences varying temperatures.
Characteristics of Double Pipe Heat Exchangers
- Double pipe heat exchangers are used when heat transfer area required is very low.
- They occupy a small area and are inexpensive.
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Description
Multiple choice questions on heat exchangers, including types, heat transfer methods, and flow arrangements. Test your knowledge on heat exchangers and their applications.
