A black spherical ball (epsilon = 0.95) at 125°C is suspended in air. It loses heat...
A black spherical ball (epsilon = 0.95) at 125°C is suspended in air. It loses heat by convection to the surrounding air at 25°C with an associated convection heat transfer coefficient of 12 W·m-2·K-1 and by radiation to the surrounding surfaces at 15°C. Assuming steady state conditions, determine the heat transfer flux due to convection and radiation.
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A black spherical ball (epsilon = 0.95) at 125°C is suspended in
air. It loses heat...
3. A spherical ball having a diameter of 5 mm and at a temperature of 90°C...
3. A spherical ball having a diameter of 5 mm and at a temperature of 90°C is covered by a 3 mm thick plastic insulation. The ball is exposed to air at 24°C, with a combined convection and radiation heat transfer coefficient of 35 W/m² °C. Determine if the plastic insulation on the ball will help or hurt heat transfer from the ball.
please help me. Thanks Consider the spherical ball shown in the figure below has a diameter...
please help me. Thanks
Consider the spherical ball shown in the figure below has a diameter of 0.65m, and is at a temperature of 550°C. The ball is suspended in air. If the emissivity of the ball surface is 0.7, calculate the heat transfer rate by radiation from the ball into the surrounding. The surrounding temperature is 15°C. Ball [5 Mark Heat transfer rate:
2 ICED WATER IN A SPHERICAL CONTAINER (10 POINTS) Troom = 30°C Iced water O ,...
2 ICED WATER IN A SPHERICAL CONTAINER (10 POINTS) Troom = 30°C Iced water O , D; = 5 m 1.5 cm T = 0°C A 5-m-internal-diameter spherical tank made of 1.5-cm-thick stainless steel (k = 15 W/( m K )) is used to store iced water at 0°C. The tank is located in a room whose temperature is 30°C. The walls of the room are also at 30°C. Heat transfer between the outer surface of the tank and the...
4. Mixed-Mode Heat Transfer - A transistor capsule is roughly spherical with a 1 cm diameter,...
4. Mixed-Mode Heat Transfer - A transistor capsule is roughly spherical with a 1 cm diameter, covered by a very thin dielectric coating with radiation emissivity E 0.85 The transistor surface is at 60 °C and the surrounding air is at 30°C. The transistor is contained by the black walls of a spherical case with temperature 35 °C, where the case walls are located at a distance H 10 cm from the transistor capsule wall. a) Find the rate of...
Two large parallel plates with surface conditions approximating those of a blackbody are maintained at 800°C...
Two large parallel plates with surface conditions approximating those of a blackbody are maintained at 800°C and 100°C, respectively. Determine the rate of heal transfer by radiation between the plates in Wim and the radiative heat transfer coefficient in W/m K ) 12 Write down the one-dimensional sent heal conduction equation for a plane wall with constant thermal conductivity and heat generation in its simplest form, and indicate what each variable represents 13 Write down the one-dimensional transient heat conduction...
A) Determine the convection heat transfer coefficient for the flow of air. [W/m2·°C] B) Determine the...
A) Determine the convection
heat transfer coefficient for the flow of air.
[W/m2·°C]
B) Determine the convection heat transfer coefficient for water.
[W/m2·°C]
The velocity of the fluid is 9 m/s in an 8-cm diameter and 7-m-long tube when the tube is subjected to uniform heat flux from all surfaces. Use fluid properties at 25°C. Water or Air D 8 cm L=7 m Given: The properties of air at 25°C are: k 0.02551 W/m."C v 1.562 10-5 m2/s Pr =...
Sphere is made of Silver. The air is still so Heat transfer would be Free Convection A sphere of silver of 30 mm diameter is cooling suspended in still air at room temperature of 27°C. If the initial...
Sphere is made of Silver. The air is still so Heat transfer
would be Free Convection
A sphere of silver of 30 mm diameter is cooling suspended in still air at room temperature of 27°C. If the initial temperature of the sphere is 127°C, what will be its center temperature after 15 minutes? Ignore the radiation effects
A sphere of silver of 30 mm diameter is cooling suspended in still air at room temperature of 27°C. If the initial temperature...
Problem 2. A long thin alloy wire with a diameter of 0.2 mm is exposed to...
Problem 2. A long thin alloy wire with a diameter of 0.2 mm is exposed to ambient air at T, -25°C with a combined heat transfer coefficient h-10 W/m2.K (due to natural convection and radiation). An electric current10.15 A flows through the wire. The electrical resistance of the wire per unit length is R-162/m. (a) Draw a control volume to write down the energy balance equation. (b) Determine the steady-state temperature of the alloy wire, assuming that the solid wire...
Problem 1 (25 points) In an experiment to measure heat transfer coefficients, a very thin foil...
Problem 1 (25 points) In an experiment to measure heat transfer coefficients, a very thin foil of low emissivi attached to a slab of material with low thermal conductivity. The other surface of the metal foil is exposed to convection heat transfer by fluid flowing over the foil surface. The slab on which the metal foil is attached has a thickness of 30 mm and a thermal conductivity of 0.023 W/m K in a condition where the surrounding room temperature...
Question You are studying heat transfer through a spherical shell container with a thermal conductivity k....
Question You are studying heat transfer through a spherical shell container with a thermal conductivity k. The inner and outer radii are identified as a and b, respectively. The inside surface of the shell is exposed to a constant heat flux in the outward direction. The outside surface temperature of the container is measured at Note that only the variables values provided in the problem statement are known. Assume steady one-dimensional radial heat transfer a. Give the mathematical formulation of...
3. A spherical ball having a diameter of 5 mm and at a temperature of 90°C is covered by a 3 mm thick plastic insulation. The ball is exposed to air at 24°C, with a combined convection and radiation heat transfer coefficient of 35 W/m² °C. Determine if the plastic insulation on the ball will help or hurt heat transfer from the ball.
please help me. Thanks
Consider the spherical ball shown in the figure below has a diameter of 0.65m, and is at a temperature of 550°C. The ball is suspended in air. If the emissivity of the ball surface is 0.7, calculate the heat transfer rate by radiation from the ball into the surrounding. The surrounding temperature is 15°C. Ball [5 Mark Heat transfer rate:
2 ICED WATER IN A SPHERICAL CONTAINER (10 POINTS) Troom = 30°C Iced water O , D; = 5 m 1.5 cm T = 0°C A 5-m-internal-diameter spherical tank made of 1.5-cm-thick stainless steel (k = 15 W/( m K )) is used to store iced water at 0°C. The tank is located in a room whose temperature is 30°C. The walls of the room are also at 30°C. Heat transfer between the outer surface of the tank and the...
4. Mixed-Mode Heat Transfer - A transistor capsule is roughly spherical with a 1 cm diameter, covered by a very thin dielectric coating with radiation emissivity E 0.85 The transistor surface is at 60 °C and the surrounding air is at 30°C. The transistor is contained by the black walls of a spherical case with temperature 35 °C, where the case walls are located at a distance H 10 cm from the transistor capsule wall. a) Find the rate of...
Two large parallel plates with surface conditions approximating those of a blackbody are maintained at 800°C and 100°C, respectively. Determine the rate of heal transfer by radiation between the plates in Wim and the radiative heat transfer coefficient in W/m K ) 12 Write down the one-dimensional sent heal conduction equation for a plane wall with constant thermal conductivity and heat generation in its simplest form, and indicate what each variable represents 13 Write down the one-dimensional transient heat conduction...
A) Determine the convection
heat transfer coefficient for the flow of air.
[W/m2·°C]
B) Determine the convection heat transfer coefficient for water.
[W/m2·°C]
The velocity of the fluid is 9 m/s in an 8-cm diameter and 7-m-long tube when the tube is subjected to uniform heat flux from all surfaces. Use fluid properties at 25°C. Water or Air D 8 cm L=7 m Given: The properties of air at 25°C are: k 0.02551 W/m."C v 1.562 10-5 m2/s Pr =...
Sphere is made of Silver. The air is still so Heat transfer
would be Free Convection
A sphere of silver of 30 mm diameter is cooling suspended in still air at room temperature of 27°C. If the initial temperature of the sphere is 127°C, what will be its center temperature after 15 minutes? Ignore the radiation effects
A sphere of silver of 30 mm diameter is cooling suspended in still air at room temperature of 27°C. If the initial temperature...
Problem 2. A long thin alloy wire with a diameter of 0.2 mm is exposed to ambient air at T, -25°C with a combined heat transfer coefficient h-10 W/m2.K (due to natural convection and radiation). An electric current10.15 A flows through the wire. The electrical resistance of the wire per unit length is R-162/m. (a) Draw a control volume to write down the energy balance equation. (b) Determine the steady-state temperature of the alloy wire, assuming that the solid wire...
Problem 1 (25 points) In an experiment to measure heat transfer coefficients, a very thin foil of low emissivi attached to a slab of material with low thermal conductivity. The other surface of the metal foil is exposed to convection heat transfer by fluid flowing over the foil surface. The slab on which the metal foil is attached has a thickness of 30 mm and a thermal conductivity of 0.023 W/m K in a condition where the surrounding room temperature...
Question You are studying heat transfer through a spherical shell container with a thermal conductivity k. The inner and outer radii are identified as a and b, respectively. The inside surface of the shell is exposed to a constant heat flux in the outward direction. The outside surface temperature of the container is measured at Note that only the variables values provided in the problem statement are known. Assume steady one-dimensional radial heat transfer a. Give the mathematical formulation of...
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