The electrical work of 550 W is needed to heat up the plate of a dish...
The electrical work of 550 W is needed to heat up the plate of a dish heater. The heater is exposed to the air at 20°C. The convection heat transfer coefficient between the plate surface and the surrounding air is 35 W/m2.°C. If the dish heater plate with a surface area of 0.01 m2, is at 677°C, determine the emissivity of the plate of the dish heater?
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The electrical work of 550 W is needed to heat up the plate of a
dish...
A 50 mm thick steel plate (AISI347) has a uniform heat flux applied to its bottom...
A 50 mm thick steel plate (AISI347) has a uniform heat flux
applied to its bottom surface by a heater. The heater is in contact
with the steel plate, and the interface between the heater and
steel has a contact resistance of 2.0 x 10-4
m2*K/W. The top surface of the plate is exposed to
surrounding air (T = 20oC, h = 10 W/m2*K) and
exchanges radiation with surroundings at Tsur =
10oC. The emissivity of the plate is 0.85....
1. Consider an opaque, horizontal square plate (Im by 1m) with an electrical heater on its backside. The front side is exposed to ambient quiescent air that is at 20° C, solar irradiation (from...
1. Consider an opaque, horizontal square plate (Im by 1m) with an electrical heater on its backside. The front side is exposed to ambient quiescent air that is at 20° C, solar irradiation (from sun at 5800° K) of 600 W/m2, and an effective sky temperature of -40° C. The plate surface temperature is kept at Ts 60 C (at steady state condition). Calculate natural convection heat transfer coefficient from the plate. (10 points) What is the electrical power (W/m2)...
A flat plate is maintained at 400 degrees C and it is well insulated around the...
A flat plate is maintained at 400 degrees C and it is well insulated around the sides and bottom. The plate experiences 800 w/m^2 of irradiation from its surroundings. The surrounding air is at 40 degrees C. The surrounding 40C air provides a convection coefficient of 15 w/m^2K. The plate surface has an emissivity of 0.9 and an absorptivity (for all irradiation) of 0.7. What is the net heat transfer.
A wall panel is insulated on the back and exposed to solar radiation on the front...
A wall panel is insulated on the back and exposed to solar radiation on the front surface. The exposed surface of the plate has an absorptivity α = 0.8 for radiation (i.e. 80% of radiant energy is absorbed). Solar radiation arrives to the panel at a rate of 1 kW⁄m2. The panel emissivity ϵ = 1 and the surrounding air temperature is 25°C. a. If we assume radiation is the only mechanism of heat transfer, in this scenario determine the...
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...
An aluminum plate with a thickness of L=5 mm is mounted in a horizontal position, and...
An aluminum plate with a thickness of L=5 mm is mounted in a horizontal position, and its bottom surface is well insulated. A special, thin coating (with emissivity and solar absorptivity of 0.25) is applied to the top surface. The density ρ and specific heat c of aluminum are known to be 2700 kg/m3 and 900 J/kg · K, respectively. Consider conditions for which the plate is initially at a temperature of ??????=25 °C and its top surface is suddenly...
Cold conditioned air at 10°C is flowing inside a 1.5 cm thick square aluminum (k = 240 w/mK) duct...
Cold conditioned air at 10°C is flowing inside a 1.5 cm thick square aluminum (k = 240 w/mK) duct of inner cross section of 25x25cm at a mass flow rate of 1.0 kg/s. The duct is exposed to air at 35°C with a combined convection-radiation heat transfer coefficient of 15 W/m2K. The convection heat transfer coefficient at the inner surface is 75 W/.m2.K. If the air temperature in the duct should not increase by more than 1°C determine the maximum...
2.) A plane wall is made of brick with a thermal conductivity of 1.5 W/(m-K). The...
2.) A plane wall is made of brick with a thermal conductivity of 1.5 W/(m-K). The wall is 20 cm thick and has a surface area of 10 m2. One side of the wall is exposed to outside air blowing against the wall resulting in a heat transfer coefficient of 20 W/(m2-K). The other side is exposed to an air-conditioned room with a convective heat transfer coefficient of 5 W/(m2-K). a. What are the thermal resistances corresponding to conduction through...
izon- e and sur- osed loss calm ffec- e the ce to 1-106 A nonmetal plate...
izon- e and sur- osed loss calm ffec- e the ce to 1-106 A nonmetal plate (k = 0.05 W/m.K) and an ASME SA-240 stainless steel plate (k = 15 W/m-K) are bolted together by ASTM B21 naval brass bolts. Both plates have a thickness of 38 mm, and the brass bolts are bolted through both plates. The bottom steel plate surface (surface 1) is subjected to a uniform heat flux of 200 W/m². The top non- metal plate surface...
please show me how I can finds the answers of these two examples Example 1: Design of a Solar Heater (Black bodies: no convection) A square flat plate collector is exposed to solar radiation from...
please show me how I can finds the answers of these two
examples
Example 1: Design of a Solar Heater (Black bodies: no convection) A square flat plate collector is exposed to solar radiation from both the sides. The exposed surface of the plate has an absorptivity of 1.0 for solar radiation. On a clear summer day on the earth's surface the solar radiation flux is approximately 1140 W/m2 and the surrounding air temperature is 25oC. Determine the surface temperature?...
A 50 mm thick steel plate (AISI347) has a uniform heat flux
applied to its bottom surface by a heater. The heater is in contact
with the steel plate, and the interface between the heater and
steel has a contact resistance of 2.0 x 10-4
m2*K/W. The top surface of the plate is exposed to
surrounding air (T = 20oC, h = 10 W/m2*K) and
exchanges radiation with surroundings at Tsur =
10oC. The emissivity of the plate is 0.85....
1. Consider an opaque, horizontal square plate (Im by 1m) with an electrical heater on its backside. The front side is exposed to ambient quiescent air that is at 20° C, solar irradiation (from sun at 5800° K) of 600 W/m2, and an effective sky temperature of -40° C. The plate surface temperature is kept at Ts 60 C (at steady state condition). Calculate natural convection heat transfer coefficient from the plate. (10 points) What is the electrical power (W/m2)...
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...
Cold conditioned air at 10°C is flowing inside a 1.5 cm thick square aluminum (k = 240 w/mK) duct of inner cross section of 25x25cm at a mass flow rate of 1.0 kg/s. The duct is exposed to air at 35°C with a combined convection-radiation heat transfer coefficient of 15 W/m2K. The convection heat transfer coefficient at the inner surface is 75 W/.m2.K. If the air temperature in the duct should not increase by more than 1°C determine the maximum...
2.) A plane wall is made of brick with a thermal conductivity of 1.5 W/(m-K). The wall is 20 cm thick and has a surface area of 10 m2. One side of the wall is exposed to outside air blowing against the wall resulting in a heat transfer coefficient of 20 W/(m2-K). The other side is exposed to an air-conditioned room with a convective heat transfer coefficient of 5 W/(m2-K). a. What are the thermal resistances corresponding to conduction through...
izon- e and sur- osed loss calm ffec- e the ce to 1-106 A nonmetal plate (k = 0.05 W/m.K) and an ASME SA-240 stainless steel plate (k = 15 W/m-K) are bolted together by ASTM B21 naval brass bolts. Both plates have a thickness of 38 mm, and the brass bolts are bolted through both plates. The bottom steel plate surface (surface 1) is subjected to a uniform heat flux of 200 W/m². The top non- metal plate surface...
please show me how I can finds the answers of these two
examples
Example 1: Design of a Solar Heater (Black bodies: no convection) A square flat plate collector is exposed to solar radiation from both the sides. The exposed surface of the plate has an absorptivity of 1.0 for solar radiation. On a clear summer day on the earth's surface the solar radiation flux is approximately 1140 W/m2 and the surrounding air temperature is 25oC. Determine the surface temperature?...
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