7-34 An array of power transistors, dissipating 5 W of power each, are to be cooled by mounting them on a 25-cm x 25-cm-square aluminum plate and blowing air at 35°C over the plate with a fan at avelocity of 4 m/s. The average temperature of the plate is not to exceed 65°C. Assuming the heat transfer from the back side of the plate to be negligible and disregarding radiation, determine the numberof transistors that can be placed on this plate.FIGURE P7-34AluminumPowerplatetransistor, 5 W35°C25 cmAir →4 m/s-65°C25 cm

Determine the average film temperature by using the information given in the question. Here, Ts is…

Answered: 7-34 An array of power transistors,…

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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Plasma spraying is a process used to coat the surface of a material with a protective layer to prevent material degradation. In a plasma spray process, the protective coating in powder form is injected into a plasma jet. The powder is then heated until the droplets coalesce and are propelled over the surface of the material. Once deposited on the surface of the material, the molten droplets solidify and form a protective coating layer. Consider a plasma spray process using alumina (k = 30 W/m K, ρ = 3970 kg/m³ and cp = 800 J/kg K) powder that is injected into a plasma jet at T∞ = 15,000 ° C and h = 10,000 W/m²·K. Alumina powder is made up of spherically shaped particles with a mean diameter of 60 μm and a melting point of 2300 °C. Determine the amount of time it would take for the particles, with an initial temperature of 20 °C, to reach their melting point from the time they are injected into the plasma jet. Note: Give the solution from fundamental concepts of how the heat flow…
In a dairy operation, milk at a flow rate of 0.25m3/hr and a cow-body temperature of 38.6°C must be chilled to a safe-to- store temperature of 13°C. Cold water at 2.2°C is available at a flow rate of 0.94m3/hr. The density and specific heat of milk are 1030 kg/m3 and 3860 J/kg.K, respectively. The density and specific heat of water is 1000 kg/m3 and 4187 J/kg.K. The chilling process is done by a double pipe counter-flow exchanger with an overall heat transfer coefficient U=1000 W/m2.K. The pipe of the heat exchanger has a 50-mm diameter with negligible thickness. Determine the pipe length L required. Select one: O a. 2.28 m O b. 4.28 m O c. 3.28 m O d. 1.28 m
Plasma spraying is a process used to coat the surface of a material with a protective layer to prevent material degradation. In a plasma spray process, the protective coating in powder form is injected into a plasma jet. The powder is then heated until the droplets coalesce and are propelled over the surface of the material. Once deposited on the surface of the material, the molten droplets solidify and form a protective coating layer. Consider a plasma spray process using alumina (k = 30 W/m K, ρ = 3970 kg/m³ and cp = 800 J/kg K) powder that is injected into a plasma jet at T∞ = 15,000 ° C and h = 10,000 W/m²·K. Alumina powder is made up of spherical-shaped particles with a mean diameter of 60 μm and a melting point of 2300 °C.Solving, the amount of time it would take for the particles, with an initial temperature of 20 °C, to reach their melting point from the time they are injected into the plasma jet is 5,25x10 -4 s. Explain how the heat flow behaves in the system, using the…
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A 5m copper tube is heated externally to 100degC. Air is heated by passing it through the 40mm diameter tube, h=0.03375kW/m²-K. The air enters the tube at 20degC and leaves at 88degC. The average air velocity is 8m/s. Calculate the heat transfer in kW
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Please solve this question, thank you very much
student was asked to do an experiment on a refrigerator test kit during an undergraduate laboratory class in an engineering college. He conducted the experiment for a period of 30 minute and measured that the refrigerated space is maintained at -5°C, while the temperature of the laboratory is 20°C. According to his experiment, it has found that during the experiment the refrigerator draws 1 kWh of electrical energy and 40000 kJ of heat is removed from the refrigerated space. Do you think there is an error in his experiment?

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