Problem 5.067 on one of its surfaces. The temperature of the water is 25C, and the...
Problem 5.067 on one of its surfaces. The temperature of the water is 25C, and the Jets maintals an esdtremely lerpe aperastimutely unlform cenwetion cosficent at the surface: Aosuming that the surface s maintained at the temratired w th distance of 26 mm from the surface? the temperature of the water theoughout the coing,how ng wiliae for tetrature to each S0 It will take L
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Problem 5.067 on one of its surfaces. The temperature of the
water is 25C, and the...
A furnace has the form of a truncated conical section, perfectly insulated with an emissivity of...
A furnace has the form of a truncated conical section, perfectly insulated with an emissivity of 0.3. Assume that all the surfaces are diffuse-gray. s shown in the schematic. The floor of the furnace hasa emissivity of e 0.7 and is maintained at 1000 K with a heat flux of 2200 W/m2, The lateral wall is D 20 mm A L 50 mm A D, 40 mm (a) Determine the temperature of the upper surface, T, if its emissivity is...
Supplemental Problem 7.001 A flat plate of width 1 m is maintained at a uniform surface temperatu...
Supplemental Problem 7.001 A flat plate of width 1 m is maintained at a uniform surface temperature of Ts = 160°C by using independently of thickness a 12 mm and length b 50 mm. plate at a velocity of 30 m/s. The thermophysical properties of the module are k Reynolds number is 5x105 rectangular modules Each module is insulated from its neighbors, as well as on its back side. Atmospheric air at 25%C flows over the 5.2 w/m-K, cp320 J/kg...
Problem 2: A 25 mm thick glass sheet needs to be rapidly quenched by air jets...
Problem 2: A 25 mm thick glass sheet needs to be rapidly quenched by air jets (h-800 W/m2-K, T-25°C) on both sides to "temper" it. The glass starts at an initial temperature of 800°C, and its surface must be cooled to less than 150°C. (a) What type of transient analysis is appropriate for this problem? You must justify your answer. (b) How long would this process take? (c) What is the glass centerline temperature at that time?
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal diffusivity of water is 0.143 10-6 m2/s. H...
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal diffusivity of water is 0.143 10-6 m2/s. How long will it take for water 5 cm below the surface to rise to 285 K.
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal...
An ice cube floats in a beaker of ice cold water. Since the water is ice...
An ice cube floats in a beaker of ice cold water. Since the water is ice cold, the ice cube is not melting and hence its volume is not changing. The density of water and ice are, respectively, ρw = 1,000 kg/m3 and ρi = 917 kg/m3. (Assume one of the ice cube's faces is parallel to the water's surface.) (a) If the ice cube is 17.0 mm on each side, how far below the surface (in mm) is the...
PRINTER VERSION BACK NEXT RCES Supplemental Problem 7.001 A flat plate of width 1 m is...
PRINTER VERSION BACK NEXT RCES Supplemental Problem 7.001 A flat plate of width 1 m is maintained at a uniform surface temperature of T,-160°C by using independently controlled, heat-generating rectangular modules of thickness a 10 mm and length b 50 mm. Each module is insulated from its neighbors, as well as on its back side. Atmospheric air at 25°C flows over the plate at a velocity of 30 m/s. The thermophysical properties of the module are k5.2 W/m K, cp...
Problem 3 (30 Points) Consider a specific application where a synthetic engine oil is used as...
Problem 3 (30 Points) Consider a specific application where a synthetic engine oil is used as a working fluid in a journal bearing with a gap between the top & bottom surfaces of L=0.6 mm. Here, the top surface moves to the left with a constant velocity (Vr) of 16 m/s, while at the same time the bottom surface moves to the right with a constant velocity (Vb) of 9 m/s. The top surface is isothermal as it is maintained...
Homework 7 heat transfer 2018-20 1) A horizontal tube of 12.5-mm dimeter with an outer srface temperature of 240°C is placed in a room with an air temperature of 20°C. Estimate the heat transfer rate...
Homework 7 heat transfer 2018-20 1) A horizontal tube of 12.5-mm dimeter with an outer srface temperature of 240°C is placed in a room with an air temperature of 20°C. Estimate the heat transfer rate per unit length of the tube due to free convection. 2) Air at -10°C flows at 10 m/s over the roof plate of two 5m length rooms whose air is at Too-200C. The roof plate is 0.20-m thick concrete (k = 0.6 w/ m. K)....
An electronic device operates in air at an ambient temperature of 22°C with a convection heat...
An electronic device operates in air at an ambient temperature of 22°C with a convection heat transfer coefficient of 85 W m K- To enhance cooling, aluminium 2024-T6 fins of length 40 mm and cross-section 2 mm x 2 mm will be mounted on one surface of the device. The finned surface measures 45 mm x 64 mm and the other surfaces are insulated. The device dissipates 95 W of heat. (i) Calculate the rate of heat transfer through one...
Radiation heat transfer: Two perfectly black surfaces (each with emissivity ε = 1.0) are constructed such...
Radiation heat transfer: Two perfectly black surfaces (each with emissivity ε = 1.0) are constructed such that all the radiant energy leaving a surface at 800 °C (1073 K) reaches the other surface. The temperature of the other surface, with area A = 2 m2, is maintained at 250 °C (523 K). Using the formula Q = ε σ A (THot4 – TCold4) calculate the heat transfer (in kW) of the surface maintained at 800 °C. The Stefan-Boltzmann constant, σ...
A furnace has the form of a truncated conical section, perfectly insulated with an emissivity of 0.3. Assume that all the surfaces are diffuse-gray. s shown in the schematic. The floor of the furnace hasa emissivity of e 0.7 and is maintained at 1000 K with a heat flux of 2200 W/m2, The lateral wall is D 20 mm A L 50 mm A D, 40 mm (a) Determine the temperature of the upper surface, T, if its emissivity is...
Supplemental Problem 7.001 A flat plate of width 1 m is maintained at a uniform surface temperature of Ts = 160°C by using independently of thickness a 12 mm and length b 50 mm. plate at a velocity of 30 m/s. The thermophysical properties of the module are k Reynolds number is 5x105 rectangular modules Each module is insulated from its neighbors, as well as on its back side. Atmospheric air at 25%C flows over the 5.2 w/m-K, cp320 J/kg...
Problem 2: A 25 mm thick glass sheet needs to be rapidly quenched by air jets (h-800 W/m2-K, T-25°C) on both sides to "temper" it. The glass starts at an initial temperature of 800°C, and its surface must be cooled to less than 150°C. (a) What type of transient analysis is appropriate for this problem? You must justify your answer. (b) How long would this process take? (c) What is the glass centerline temperature at that time?
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal diffusivity of water is 0.143 10-6 m2/s. How long will it take for water 5 cm below the surface to rise to 285 K.
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal...
PRINTER VERSION BACK NEXT RCES Supplemental Problem 7.001 A flat plate of width 1 m is maintained at a uniform surface temperature of T,-160°C by using independently controlled, heat-generating rectangular modules of thickness a 10 mm and length b 50 mm. Each module is insulated from its neighbors, as well as on its back side. Atmospheric air at 25°C flows over the plate at a velocity of 30 m/s. The thermophysical properties of the module are k5.2 W/m K, cp...
Problem 3 (30 Points) Consider a specific application where a synthetic engine oil is used as a working fluid in a journal bearing with a gap between the top & bottom surfaces of L=0.6 mm. Here, the top surface moves to the left with a constant velocity (Vr) of 16 m/s, while at the same time the bottom surface moves to the right with a constant velocity (Vb) of 9 m/s. The top surface is isothermal as it is maintained...
Homework 7 heat transfer 2018-20 1) A horizontal tube of 12.5-mm dimeter with an outer srface temperature of 240°C is placed in a room with an air temperature of 20°C. Estimate the heat transfer rate per unit length of the tube due to free convection. 2) Air at -10°C flows at 10 m/s over the roof plate of two 5m length rooms whose air is at Too-200C. The roof plate is 0.20-m thick concrete (k = 0.6 w/ m. K)....
An electronic device operates in air at an ambient temperature of 22°C with a convection heat transfer coefficient of 85 W m K- To enhance cooling, aluminium 2024-T6 fins of length 40 mm and cross-section 2 mm x 2 mm will be mounted on one surface of the device. The finned surface measures 45 mm x 64 mm and the other surfaces are insulated. The device dissipates 95 W of heat. (i) Calculate the rate of heat transfer through one...
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