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A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.
Correct answer is between '2.5,3.5'. Can you explain this answer?
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A test is conducted to determine the overall heat transfer coefficient...
Given data:
- Number of tubes: 40
- Inner diameter of tubes: 0.5 cm
- Length of tubes: 65 cm
- Hot water inlet temperature: 90°C
- Hot water outlet temperature: 60°C
- Water flow rate: 0.6 kg/s
- Air inlet temperature: 20°C
- Air outlet temperature: 40°C
- Specific heat of water: 4.195 kJ/kg-K
Calculation:
1. Calculate the heat transfer rate:
- q = m_dot * C_p * (T_hot,in - T_hot,out)
- q = 0.6 * 4.195 * (90 - 60)
- q = 75.51 kW
2. Calculate the log mean temperature difference (∆Tlm):
- ∆Tlm = [(T_hot,in - T_air,out) - (T_hot,out - T_air,in)] / ln[(T_hot,in - T_air,out) / (T_hot,out - T_air,in)]
- ∆Tlm = [(90-40) - (60-20)] / ln[(90-40) / (60-20)]
- ∆Tlm = 35.72°C
3. Calculate the overall heat transfer coefficient (U):
- q = U * A * ∆Tlm
- A = Number of tubes * π * D * L
- A = 40 * π * 0.005 * 0.65
- A = 0.41 m^2
- U = q / (A * ∆Tlm)
- U = 75.51 / (0.41 * 35.72)
- U ≈ 2.99 kW/m^2-K
Therefore, the overall heat transfer coefficient of the radiator based on the inner surface area of the tubes is approximately 2.99 kW/m^2-K, which falls within the range of 2.5 to 3.5 kW/m^2-K as the correct answer.
- Number of tubes: 40
- Inner diameter of tubes: 0.5 cm
- Length of tubes: 65 cm
- Hot water inlet temperature: 90°C
- Hot water outlet temperature: 60°C
- Water flow rate: 0.6 kg/s
- Air inlet temperature: 20°C
- Air outlet temperature: 40°C
- Specific heat of water: 4.195 kJ/kg-K
Calculation:
1. Calculate the heat transfer rate:
- q = m_dot * C_p * (T_hot,in - T_hot,out)
- q = 0.6 * 4.195 * (90 - 60)
- q = 75.51 kW
2. Calculate the log mean temperature difference (∆Tlm):
- ∆Tlm = [(T_hot,in - T_air,out) - (T_hot,out - T_air,in)] / ln[(T_hot,in - T_air,out) / (T_hot,out - T_air,in)]
- ∆Tlm = [(90-40) - (60-20)] / ln[(90-40) / (60-20)]
- ∆Tlm = 35.72°C
3. Calculate the overall heat transfer coefficient (U):
- q = U * A * ∆Tlm
- A = Number of tubes * π * D * L
- A = 40 * π * 0.005 * 0.65
- A = 0.41 m^2
- U = q / (A * ∆Tlm)
- U = 75.51 / (0.41 * 35.72)
- U ≈ 2.99 kW/m^2-K
Therefore, the overall heat transfer coefficient of the radiator based on the inner surface area of the tubes is approximately 2.99 kW/m^2-K, which falls within the range of 2.5 to 3.5 kW/m^2-K as the correct answer.
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Community Answer
A test is conducted to determine the overall heat transfer coefficient...
: 
Q = mhcph(Thi - The)
Q = 0.6 x 4.195 x (90-65)
Q = 62.93 kW
Tube side area for heat transfer, Ai = n π D L
⇒ Ai = 40 x π x 0.005 x 0.65
⇒ Ai = 0.408 m2
Again θi = 90-40 = 50OC
Θe = 65-20 =45oC
= 47.5oC
Now Q = UiAiθm
⇒ Ui = Q/Aiθm = 62.93/0.408 x 47.5
⇒ Ui = 3.247 kW/m2-K
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A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer?
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A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer?.
A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer?.
Solutions for A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer? in English & in Hindi are available as part of our courses for Mechanical Engineering.
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A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer?, a detailed solution for A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer? has been provided alongside types of A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice A test is conducted to determine the overall heat transfer coefficient in an automotive radiator that is a water-to-air heat exchanger with both fluids (air and water) unmixed. The radiator has 40 tubes of internal diameter 0.5 cm and length 65 cm in a closely spaced platefinned matrix. Hot water enters the tubes at 90oC at a rate of 0.6 kg/s and leaves at 60oC. Air flows across the radiator through the inter-fin spaces and is heated from 20oC to 40oC. Determine the overall heat transfer coefficient (in kW/m2-K) of this radiator based on the inner surface area of the tubes. Take specific heat of water as 4.195 kJ/kg-K? Consider the heat exchanges to be counter flow.Correct answer is between '2.5,3.5'. Can you explain this answer? tests, examples and also practice Mechanical Engineering tests.
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