from the back side of the board to a medium at 37°C, with a heat transfer coefficient of 45 W/m²-K. (a) Determine the surface temperatures on the two sides of the circuit board. (b) Now a 0.1-cm-thick, 10-cm-high, and 15-cm-long alumi- num plate (k = 237 W/m-K) with 20 0.2-cm-thick, 2-cm-long, and 15-cm-wide aluminum fins of rectangular profile are at- tached to the back side of the circuit board with a 0.03-cm- thick epoxy adhesive (k = 1.8 W/m-K). Determine the new temperatures on the two sides of the circuit board. Electronic components Fin 15 cm 10.3 cm 10 cm 0.2 cm - 20 fins 2 cm 1 mm 2 mm FIGURE P3-190

from the back side of the board to a medium at 37°C, with a heat transfer coefficient of 45 W/m²-K. (a) Determine the surface temperatures on the two sides of the circuit board. (b) Now a 0.1-cm-thick, 10-cm-high, and 15-cm-long alumi- num plate (k = 237 W/m-K) with 20 0.2-cm-thick, 2-cm-long, and 15-cm-wide aluminum fins of rectangular profile are at- tached to the back side of the circuit board with a 0.03-cm- thick epoxy adhesive (k = 1.8 W/m-K). Determine the new temperatures on the two sides of the circuit board. Electronic components Fin 15 cm 10.3 cm 10 cm 0.2 cm - 20 fins 2 cm 1 mm 2 mm FIGURE P3-190

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.

Chapter2: Steady Heat Conduction

Section: Chapter Questions

Problem 2.38P: 2.38 The addition of aluminum fins has been suggested to increase the rate of heat dissipation from...

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Required Information The upper surface of a 85-cm-thick solid plate (k= 237 W/m-K) is being cooled by water with temperature of 20°C. The upper and lower surfaces ofthe solid plate maintained at constant temperatures of 60°C and 120°C, respectively. Given: The thermal conductivity of the solid plate is given ask= 237 W/m K. f2 (T,1+T) = (60°C + 20°C)/2 = 40°C is kuid = 0.631 The thermal conductivity of water at the film temperature of T; W/m/K. Determine the water convection heat transfer coefficient. The water convection heat transfer coefficient is W/m2 -K.
google.com ube Maps Electrically heated draw batch furnaces are commonly used in the heat treatment industry. Consider a draw batch furnace front made of a 20-mm thick steel plate with a ther- mal conductivity of 25 W/m-K. The furnace is situated in a room with surrounding air temperature of 20°C and an aver- age convection heat transfer coefficient of 10 W/m2-K. If the inside surface of the furnace front is subjected to uniform heat flux of 5 kW/m² and the outer surface has an emissiv- ity of 0.30, determine the inside surface temperature of the furnace front. = 20°C Furnace fron 4, = 5 kW/m Air, 20 C h= 10 W/m K e = 0.30 kn25 W/m-K
A 5.1-m internal diameter spherical tank made of 1.6-cm-thick stainless steel (k = 15 w/m- c) is used to store iced water at 0 C. the wall of the room are also at 31 C. The convection heat transfer coefficient at the inner and the outer surface of the tank are 80 w/m - c, respectively. Determine (a) the rate of heat transfer of the iced water and (b) the amount of iced at 0 C that melts during a 24 h period. the heat of fusion of water at atmospheric pressure is 333.7 kj/kg.
Electrically heated draw batch furnaces are commonly used in the heat treatment industry. Consider a draw batch furnace front made of a 20-mm thick steel plate with a ther- mal conductivity of 25 W/m-K. The furnace is situated in a room with surrounding air temperature of 20°C and an aver- age convection heat transfer coefficient of 10 W/m²-K. If the inside surface of the furnace front is subjected to uniform heat flux of 5 kW/m? and the outer surface has an emissiv- ity of 0.30, determine the inside surface temperature of the furnace front. Turr = 20°C Furnace front 4, = 5 kW/m? Air, 20°C h = 10 W/m².K 8 = 0.30 k = 25 W/m-K To TL
Electrically heated draw batch furnaces are commonly used in the heat treatment industry. Consider a draw batch furnace front made of a 20-mm thick steel plate with a ther- mal conductivity of 25 W/m-K. The furnace is situated in a room with surrounding air temperature of 20°C and an aver- age convection heat transfer coefficient of 10 W/m²-K. If the inside surface of the furnace front is subjected to uniform heat flux of 5 kW/m² and the outer surface has an emissiv- ity of 0.30, determine the inside surface temperature of the furnace front. Tur = 20°C Furnace front 4, =5 kW/m? Air, 20°C h = 10 W/m-K 8 = 0.30 k = 25 W/m-K To
. A 6-m-long 2-kW electrical resistance wire is made of 0.2-cm-diameter stainless steel (k = 15.1 W/m °C). The re- sistance wire operates in an environment at 30°C with a heat transfer coefficient of 140 W/m². °C at the outer surface. De- termine the surface temperature of the wire (a) by using the ap- plicable relation and (b) by setting up the proper differential equation and solving it. Answers: (a) 409°C, (b) 409°C
Electrically heated draw batch furnaces are commonly used in the heat treatment industry. Consider a draw batch furnace front made of a 20-mm thick steel plate with a ther- mal conductivity of 25 W/m-K. The furnace is situated in a room with surrounding air temperature of 20°C and an aver- age convection heat transfer coefficient of 10 W/m²-K. If the inside surface of the furnace front is subjected to uniform heat flux of 5 kW/m² and the outer surface has an emissiv- ity of 0.30, determine the inside surface temperature of the furnace front. Turr = 20°C Furnace front 4, = 5 kW/m? Air, 20°C h = 10 W/m² K e = 0.30 k = 25 W/m-K To
Electrically heated draw batch furnaces are commonly used in the heat treatment industry. Consider a draw batch furnace front made of a 20-mm thick steel plate with a ther- mal conductivity of 25 W/m-K. The furnace is situated in a room with surrounding air temperature of 20°C and an aver- age convection heat transfer coefficient of 10 W/m2 K. If the inside surface of the furnace front is subjected to uniform heat flux of 5 kW/m 2 and the outer surface has an emissiv- ity of 0.30, determine the inside surface temperature of the furnace front?
A long 20 cm diameter shaft made of stainless steel 304 comes out of an oven at a uniform temperature of 600°C. The shaft is then allowed to cool slowly in an environment at 200°C with an average heat transfer coefficient of h = 80 W/m².K. Determine [a] the temperature at the center of the shaft and [b] the temperature of the outer surface of the shaft 45 minutes after the start of the cooling Given: Find: Schematic: Assume: Property Data: k= 14.9 W/m°C p= 7900 kg/m³ Cp = 477 J/kg:K a= 3.95 x 10-6 m²/s
Required information The upper surface of a 85-cm-thick solid plate (k = 237 W/m-K) is being cooled by water with temperature of 20°C. The upper and lower surfaces oNhe solid plate maintained at constant temperatures of 60°C and 120°C, respectively Given: The thermal conductivity of the solid plate is given as k= 237 W/m K. The thermal conductivity of water at the film temperature of Tf (T,1+T») = (60°C + 20°C)/2 = 40°C is k fluid = 0.631 2 W/mK. Determine the water temperature gradient at the upper plate surface. The water temperature gradient at the upper plate surface is K/m.
A 0.8-cm-thick,15-cm-high, and 20-cm-long circuit board houses 100 closely spaced logic chips on one side, each dissipating 0.05 W. The board is impregnated with copper fillings and has an effective thermal conductivity of 20 W/m-K. All the heat generated in the chips is conducted across the circuit board and is dissipated from the back side of the board to the ambient air. Determine the temperature difference between the two sides of the circuit board.
Question 4 The window of a room is made of 5 mm thick glass which has a thermal conductivity of 1.4 W/m-K. A heater is used to maintain the room temperature at 22 °C. Take the convection heat transfer coefficients on the outer surface of the window to be 12 W/m²-K. Take appropriate assumptions while solving this problem. (a) T₁-15°C TA -A=1m x 3m 3m², k=1.4 W/m-K I L=0.005m Figure Q2 ** -T₂=5°C Find the convection heat transfer coefficients on the inner surface of the window.