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A horizontal eledctric heater 25 mm in diameter is submerged in a light oil bath at...
Engine oil is heated by flowing through a circular tube of diameter D = 50 mm...
Engine oil is heated by flowing through a circular tube of diameter D = 50 mm and length L = 25 m and whose surface is maintained at 150 oC. The flow rate and inlet temperature of the oil are 0.5 kg/s and 20 oC. a. Estimate the outlet temperature Tm,o. B. Average Nusselt number C. Estimate the total heat transfer rate q for the tube.
A 10-mm diameter tube has a maintained surface temperature of 180°C. Engine oil enters the tube...
A 10-mm diameter tube has a maintained surface temperature of 180°C. Engine oil enters the tube at 70°C at a flow rate of 1.3 kg/s and exits at 105°C. Find the length, in m, of the tube and well as the corresponding heat transfer rate, in W. Assume fully developed flow and use the Dittus-Boelter equation to calculate the average Nusselt number. q= W L= m
A can of engine oil with a length of 155 mm and a diameter of 100...
A can of engine oil with a length of 155 mm and a diameter of 100 mm is placed vertically in the trunk of a car. In a hot summer day, the temperature in the trunk is 43°C. If the surface temperature of the can is 17°C, determine heat transfer rate from the can surface. Neglect the heat transfer from the ends of the can and radiation heat transfer. Given: The properties of air at film temperature of 30°C. k...
A cylindrical electric heater is located at the centre of a room. The heater has an...
A cylindrical electric heater is located at the centre of a room. The heater has an outer diameter of 0.05 m, length of 0.6 m and emmisivity of 0.97. The surface temperature of this heater is maintained at 105 °C. The internal dimension of the room is 5m x 10m x 3m. The inner surface of this room's wall and air inside this room is maintained at 20 °C using an air conditioning system. The heat transfer coefficient between the...
A circular pipe of 25-mm outside diameter and 500-mm length is placed in an airstream at...
A circular pipe of 25-mm outside diameter and 500-mm length is placed in an airstream at 25°C and 1-atm pressure. The air moves in cross flow over the pipe at 15 m/s, while the outer surface of the pipe is maintained at 100 °C, what is the rate of heat transfer from the pipe? submit you answer in W.
(40 points) Engine oil flows at a rate of 1 kg/s through a 5-mm diameter smooth straight tube. Th...
(40 points) Engine oil flows at a rate of 1 kg/s through a 5-mm diameter smooth straight tube. The oil has an inlet temperature of 47°C and it is desired to heat the oil to a mean temperature of 87°C at the exit of the tube. The surface of the tube is maintained at 150°C. Assuming the flow is fully developed both hydrodynamically and thermally, determine the required length of the tube. Note: by calculating Reynolds number at the entrance...
A long wire with circular cross section and diameter D = 1 mm is submerged in an oil bath with temperature To 20。C. The wire is initially at temperature T = 20。C, the same temperature as the oil. A...
A long wire with circular cross section and diameter D = 1 mm is submerged in an oil bath with temperature To 20。C. The wire is initially at temperature T = 20。C, the same temperature as the oil. A current is passed through the wire, resulting in a volumetric heat generation of q - 1.5 x 108 W/m3. The convection coefficient is h - 500 W/m2 - K, and the properties of the wire are ρ-8000 kg/m3, Cp-500 J/kg-K, and...
A brass rod (k = 133 W/m-K) with a diameter of 5 mm and a length...
A brass rod (k = 133 W/m-K) with a diameter of 5 mm and a length of 100 mm is used to enhance heat transfer from a surface which is maintained at 200 C. The cylindrical surface of the rod is exposed to a convection environment with h = 30 W/m2-K and an ambient temperature of 20 C. a) Calculate the heat convected away from the rod. b) Calculate the temperature 50 mm from the wall. c) Plot the temperature...
A steam main of 150 mm outside diameter containing wet steam at 28 bar is insulated...
A steam main of 150 mm outside diameter containing wet steam at 28 bar is insulated with an inner layer of diatomaceous earth, 40 mm thick, and an outer layer of 85 % magnesia, 25 mm thick. The inside surface of the pipe is at the steam temperature, and the heat transfer coefficient for the outside surface of the lagging is 17 W/m2 K. The thermal conductivities of diatomaceous earth and 85 % magnesia are 0.09, and 0.06 40 ME...
An oil preheater consists of a single tube of 30-mm diameter and 7-m length, with its...
An oil preheater consists of a single tube of 30-mm diameter and 7-m length, with its surface maintained at 200°C by swirling combustion gasses. The engine oil enters at 90°C and comes out at 144°C. Assume the flow is laminar and both hydraulically and thermally fully developed. Answer the following questions: (a) What flow rate must be supplied to maintain the oil outlet temperature of 144°C? (b) What is the corresponding heat transfer rate? (c) Discuss how you may refine...
A 10-mm diameter tube has a maintained surface temperature of 180°C. Engine oil enters the tube at 70°C at a flow rate of 1.3 kg/s and exits at 105°C. Find the length, in m, of the tube and well as the corresponding heat transfer rate, in W. Assume fully developed flow and use the Dittus-Boelter equation to calculate the average Nusselt number. q= W L= m
A cylindrical electric heater is located at the centre of a room. The heater has an outer diameter of 0.05 m, length of 0.6 m and emmisivity of 0.97. The surface temperature of this heater is maintained at 105 °C. The internal dimension of the room is 5m x 10m x 3m. The inner surface of this room's wall and air inside this room is maintained at 20 °C using an air conditioning system. The heat transfer coefficient between the...
A circular pipe of 25-mm outside diameter and 500-mm length is placed in an airstream at 25°C and 1-atm pressure. The air moves in cross flow over the pipe at 15 m/s, while the outer surface of the pipe is maintained at 100 °C, what is the rate of heat transfer from the pipe? submit you answer in W.
(40 points) Engine oil flows at a rate of 1 kg/s through a 5-mm diameter smooth straight tube. The oil has an inlet temperature of 47°C and it is desired to heat the oil to a mean temperature of 87°C at the exit of the tube. The surface of the tube is maintained at 150°C. Assuming the flow is fully developed both hydrodynamically and thermally, determine the required length of the tube. Note: by calculating Reynolds number at the entrance...
A long wire with circular cross section and diameter D = 1 mm is submerged in an oil bath with temperature To 20。C. The wire is initially at temperature T = 20。C, the same temperature as the oil. A current is passed through the wire, resulting in a volumetric heat generation of q - 1.5 x 108 W/m3. The convection coefficient is h - 500 W/m2 - K, and the properties of the wire are ρ-8000 kg/m3, Cp-500 J/kg-K, and...
An oil preheater consists of a single tube of 30-mm diameter and 7-m length, with its surface maintained at 200°C by swirling combustion gasses. The engine oil enters at 90°C and comes out at 144°C. Assume the flow is laminar and both hydraulically and thermally fully developed. Answer the following questions: (a) What flow rate must be supplied to maintain the oil outlet temperature of 144°C? (b) What is the corresponding heat transfer rate? (c) Discuss how you may refine...
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