please very urgent i need the right answer please be carfully A power transistor of 10 mm of diameter (D),and 15 mm of length (L), is cooled by an airstream with Tair =20 C, and h = 120 W/m^2.K.What is the maximum allowable powerdissipation, Pmax if the surface temperatureshould not exceed 80 C.a.0.229 Wb. 6.3 WC.1.5 Wd. 3.9 WClear my choice

Answered: A power transistor of 10 mm of diameter…

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.68P

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HEAT TRANSFER CASE: I want to know what temperature in (°F) the cylinder will have inside. It's a heat transfer problem. what is T2 ?
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The thermal conductivities of wood is kwood = 0.1W/(m°C)and air is kair = 0.0234W/(m°C). Part A If the temperature of the room is 20°C and outside is 10°C, find the rate of heat flow for a wall of wood with area = 10 m² and thickness of 5cm. O 60 W O 304 W O 34 W O 200 W O 100 W Submit Request Answer Part B The wall of wood with thickness of 5cm is now replaced with two layers of wood and a gap of air between the wood. Each layer of wood has a 2.5cm thickness and the gap is 1cm. The rate of heat flow will, decreases. increases. stay the same. Submit Request Answer Part C The temperature in the air gap will be, O 20°C, between 10°C and 20°C, O 10°C,
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SOLVE STEP BY STEP DONT USE CHATGPT There is a horizontal PVC pipe (k=0.16 W/m°C) with a diameter of 15 cm, a wall of 3 mm and a length of 8 m. The external surface of PVC is at 19 °C. Inside this pipe is placed a steel pipe (k=45 W/m.°C), 7 em in external diameter and 2 mm thick, also 8 m long, where saturated steam circulates at 0.38 m. /s and 1.3 atm pressure. The temperature of the steel is at the same temperature of the steam. The annular space between the two pipes is filled with static air. Determine the heat flow that occurs from the steam to the outside of the system.
A) A plane wall has internal heat generation and is cooled covectively at its two faces. Given : heat generation rate g=1,000W/m? | 50 wall thickness 2L= 100 mm air temp T = 20C temp within wall T(x) = 10(0.052 – x')+30 WIm.K Find thermal conductivity of the wall h% D k = A1) Wim? K A2) Find convection heat transfer coeff Solution
As shown in the sketh below, a steam pipe of 0.12-m inside diameter is insulated with a layer of calcium silicate. 1. Ts. 1} Steam 12. T8.2} Insulation (a) If the insulation is 27.5 mm thick and its inner and outer surfaces are maintained at T1 = 800 K and T2 = 490 K, respectively. what is the rate of heat loss per unit length (q') of the pipe, in W/m? (b) Determine the rate of heat loss per unit length (q'), in W/m, and outer surface temperature T2, in K, for the steam pipe with the inner surface temperature fixed at T₁ = 800 K, inner radius r₁ = 0.06 m, and outer radius r₂ = 0.14 m. The outer surface is exposed to an airflow (To = 25°C) that maintains a convection coefficient of h = 25 W/m²-K and to large surroundings for which Tsur = To = 25°C. The surface emissivity of calcium silicate is approximately 0.8.
To maximize production and minimize pumping costs, crude oil is heated to reduce its viscosity during transportation from a production field. (1) Consider a pipe-in-pipe configuration consisting of concentric steel tubes with an intervening insulating material. The inner tube is used to transport warm crude oil through cold ocean water. The inner steel pipe (k, = 45 W/m-K) has an inside diameter of D;, 1 150 mm and wall thickness f; = 20 mm while the outer steel pipe has an inside diameter of D; 2 = 250 mm and wall thickness t, = tị. Determine the maximum allowable crude oil temperature to ensure the polyurethane foam insulation (k, between the two pipes does not exceed its maximum service temperature of Tp. max = 70°C. The ocean water is at T.0 = -5°C and provides an external convection heat transfer coefficient of h. flowing crude oil is h; = 450 W/m²-K. 0.03 W/m-K) 500 W/m2-K. The convection coefficient associated with the (2) It is proposed to enhance the performance of the…
A) A plane wall has internal heat generation and is cooled covectively at its two faces. Given : 50 heat generation Tate g=1,000W / m? wall thickness 2L= 100 mm air temp T 20C temp within wall T(x)=10(0.052-x')+30 WIm.K Find thermal conductivity of the wall h%3D k = A1) WIm.K A2) Find convection heat transfer coeff Solution
As shown in the sketh below, a steam pipe of 0.12-m inside diameter is insulated with a layer of calcium silicate. 12. Ts.2} 1. Ts,1} Steam Insulation (a) If the insulation is 17.5 mm thick and its inner and outer surfaces are maintained at T,1 = 800 K and Ts,2 = 490 K, respectively, what is the rate of heat loss per unit length (q') of the pipe, in W/m? (b) Determine the rate of heat loss per unit length (q'), in W/m, and outer surface temperature T.2, in K, for the steam pipe with the inner surface temperature fixed at Ts,1 The outer surface is exposed to an airflow (T = 800 K, inner radius ri = 0.06 m, and outer radius r2 = 25°C) that maintains a convection coefficient of h = 25 W/m2-K and to = 0.1 m. large surroundings for which Tsur = T_ = 25°C. The surface emissivity of calcium silicate is approximately 0.8.
Q2- Water flows inside a steel pipe with an ID of 2.5 cm. The wall thickness is 2 mm, and the convection coefficient on the inside is 100 Wm? C. The convection coefficient on the outside is 10 W/n C. The pipe is covered with a layer of asbestos. 1-determine the thickness of the asbestos layer at the critical insulation radius of the pipe. 2-calculate the change percent of heat transfer with and without the insulation. 3-commet on your results,

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