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Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C. The mean air temperature at section (b) is _________.
cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,
At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5 kg/m-sec
cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,
At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5 kg/m-sec
Correct answer is between '220,222'. Can you explain this answer?
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Verified Answer
Hot air flowing through a metal pipe of 20 mm diameter is cooled at a ...
Assuming for the moment that the flow is laminar, the bulk velocity may be determined from the measured centre-line velocity.
Mean velocity for laminar flow through pipes is given by Umean
(Substituting property values for air at 500 K).
Since Red < 2300, the flow is laminar.
For constant heat flux boundary condition
Mean heat flux through the pipe wall between sections (a) and (b) is
Since q is given as constant along the length of the pipe
Whe re Tw is the wall temperature and Tm is the mean bulk temperature of air at section
(b).
Note: Temperature variation for fluid as well as wall surface is linear for the case of constant heat flux.
Mean velocity for laminar flow through pipes is given by Umean
(Substituting property values for air at 500 K).
Since Red < 2300, the flow is laminar.
For constant heat flux boundary condition
Mean heat flux through the pipe wall between sections (a) and (b) is
Since q is given as constant along the length of the pipe
Whe re Tw is the wall temperature and Tm is the mean bulk temperature of air at section
(b).
Note: Temperature variation for fluid as well as wall surface is linear for the case of constant heat flux.
Most Upvoted Answer
Hot air flowing through a metal pipe of 20 mm diameter is cooled at a ...
°C. Assuming the temperature of the air at the outer surface of the pipe is 30°C, calculate the rate at which heat is transferred from the air to the pipe at section (a).
To calculate the rate at which heat is transferred from the air to the pipe at section (a), we can use the convective heat transfer equation:
Q = h * A * (T_wall - T_air)
Where:
Q = heat transfer rate (W)
h = convective heat transfer coefficient (W/m^2·K)
A = surface area of the pipe (m^2)
T_wall = temperature of the pipe wall (°C)
T_air = temperature of the air (°C)
First, we need to calculate the convective heat transfer coefficient, h. The convective heat transfer coefficient depends on various factors such as flow conditions, surface roughness, and fluid properties. In this case, we can assume a typical convective heat transfer coefficient for air flow in a pipe, which is around 50 W/m^2·K.
Next, we need to calculate the surface area of the pipe, A. The surface area of a pipe can be calculated using the formula:
A = π * D * L
Where:
D = diameter of the pipe (m)
L = length of the pipe (m)
In this case, the diameter of the pipe is 20 mm, which is equivalent to 0.02 m.
Now, we can calculate the surface area of the pipe:
A = π * 0.02 m * L
Finally, we can substitute the values into the convective heat transfer equation to find the heat transfer rate, Q:
Q = 50 W/m^2·K * A * (T_wall - T_air)
The temperature of the pipe wall, T_wall, is 250°C, and the temperature of the air, T_air, is 30°C.
Note: The convective heat transfer coefficient, h, is an estimate and can vary depending on the specific conditions.
To calculate the rate at which heat is transferred from the air to the pipe at section (a), we can use the convective heat transfer equation:
Q = h * A * (T_wall - T_air)
Where:
Q = heat transfer rate (W)
h = convective heat transfer coefficient (W/m^2·K)
A = surface area of the pipe (m^2)
T_wall = temperature of the pipe wall (°C)
T_air = temperature of the air (°C)
First, we need to calculate the convective heat transfer coefficient, h. The convective heat transfer coefficient depends on various factors such as flow conditions, surface roughness, and fluid properties. In this case, we can assume a typical convective heat transfer coefficient for air flow in a pipe, which is around 50 W/m^2·K.
Next, we need to calculate the surface area of the pipe, A. The surface area of a pipe can be calculated using the formula:
A = π * D * L
Where:
D = diameter of the pipe (m)
L = length of the pipe (m)
In this case, the diameter of the pipe is 20 mm, which is equivalent to 0.02 m.
Now, we can calculate the surface area of the pipe:
A = π * 0.02 m * L
Finally, we can substitute the values into the convective heat transfer equation to find the heat transfer rate, Q:
Q = 50 W/m^2·K * A * (T_wall - T_air)
The temperature of the pipe wall, T_wall, is 250°C, and the temperature of the air, T_air, is 30°C.
Note: The convective heat transfer coefficient, h, is an estimate and can vary depending on the specific conditions.
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Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. Can you explain this answer?
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Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. 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 Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. 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 Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. Can you explain this answer?.
Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. 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 Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. 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 Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. Can you explain this answer?.
Solutions for Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. Can you explain this answer? in English & in Hindi are available as part of our courses for Mechanical Engineering.
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Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. Can you explain this answer?, a detailed solution for Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. Can you explain this answer? has been provided alongside types of Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice Hot air flowing through a metal pipe of 20 mm diameter is cooled at a constant rate per unit length of pipe. At a particular section (a), the air velocity in the centre of the pipe is found to be 2 m/s and the wail temperature, as measured by a thermocouple on the inner surface of the pipe, is 250°C . At the section (b), situated 1 m downstream from the section (a), the wall temperature is found to be 200°C.The mean air temperature at section (b) is_________.cp = 1.03 kj/kg. K, k = 4.04 x 10-5 kW/m2K,At 500 K, p = 0.706 kg/m3 & p = 2.67 X 10-5kg/m-secCorrect answer is between '220,222'. Can you explain this answer? tests, examples and also practice Mechanical Engineering tests.
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