1. The upper surface of a 50-cm-thick solid brass plate (k-109 W/m K) is being cooled by water with temperature of 10°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 190°C, respectively. Determine the water convection heat transfer coefficient and the water temperature gradient at the upper plate surface. Water T₁,2

1. The upper surface of a 50-cm-thick solid brass plate (k-109 W/m K) is being cooled by water with temperature of 10°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 190°C, respectively. Determine the water convection heat transfer coefficient and the water temperature gradient at the upper plate surface. Water T₁,2

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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The upper surface of a 50-cm-thick solid brass plate (k=109 W/mK) is being cooled by water with temperature of 10°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 190°C, respectively. Determine the water convection heat transfer coefficient and the water temperature gradient at the upper plate surface. Water Ts.l · Ts.,2
Consider a 1.2-m-high and 2-m-wide double-panewindow consisting of two 3-mm-thick layers of glass (k =0.78 W/m·K) separated by a 3-cm-wide air space. Determinethe steady rate of heat transfer through this window and thetemperature of its inner surface for a day during which theroom is maintained at 20°C while the temperature of the outdoorsis 0°C. Take the heat transfer coefficients on the innerand outer surfaces of the window to be h1 = 10 W/m2·K andh2 = 25 W/m2·K and disregard any heat transfer by radiation.Evaluate air properties at a film temperature of 10°C and1 atm pressure. Is this a good assumption?
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A 3-m-internal-diameter spherical tank made of 1-cm-thick stainless steel is used to store iced water at 0°C. The tank is located outdoors at 25°C. Assuming the entire steel tank to be at 0°C and thus the thermal resistance of the tank to be negligible, determine (a) the rate of heat transfer to the iced water in the tank and (b) the amount of ice at 0°C that melts during a 24- hour period. The heat of fusion of water at atmospheric pressure is h = 333.7 kJ/kg. The emissivity of the outer surface of the tank is 0.75, and the convection heat transfer coefficient on the outer surface can be taken to be 30 W/m2 · °C. Assume the average surrounding surface temperature for radiation exchange to be 15°C.
The upper surface of a 50-cm-thick solid brass plate (k-109 W/mK) is being cooled by water with temperature of 10°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 190°C, respectively. Determine the water convection heat transfer coefficient and the water temperature gradient at the upper plate surface. Water Ts.1 Ts.2
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When a rectangle steel block 0.45 m by 0.65 m by 0.7m is initially at 450C. It is suddenly immersed in an environment at 101C. Determine the temperature at the center of the block after 1.5 hour. The properties are; surface convection coefficient is 43 W/m 2 .K, k= 36 W/m.K and α=0.0399 m 2 /h.
Consider a 1.5-m-high and 2.4-m-wide double-pane window consisting of two 3-mm-thick layers of glass (k=0.78 W/m-K) separated by a 12-mm-wide vacuum. Determine the steady rate of heat transfer through this double-pane window and the temperature of its inner surface for a day during which the room is maintained at 23°C while the temperature of the outdoors is -5°C. Take the convection heat transfer coefficients on the inner and outer surfaces of the window to be h=10 W/m2K and h2=25 W/m2.K, respectively, and disregard any heat transfer by radiation. Glass mm Frame The steady rate of heat transfer is The inner surface temperature of the window is W. °C.
A person is found dead at 5PM in a room whose temperature is 20°C. Thetemperature of the body is measured to be 25°C when found, Modeling thebody as a 30-cm-diameter, 1.70-m-long cylinder and the heat transfer coefficient estimated to be 8 W/m2·K. and using the lumped system analysis as a rough approximation, estimate the time of death of the person.
Consider a 0.6-m * 0.6-m thin square plate in a room at 30°C. One side of the plate is maintained at a temperature of 90°C, while the other side is insulated. Determine the rate of heat transfer from the plate by natural convection if the plate is (a) vertical, (b) horizontal with hot surface facing up, and (c) horizontal with hot surface facing down.
A 6 cm diameter cylinder is initially at a temperature of 10 °C. Later, this cylinder was thrown into water at 80°C. Calculate how long it will take for the center temperature of the cylinder to reach 50 °C by taking the convection heat transfer coefficient as 80W / /m?K. Thermal properties of the cylinder material k=0,587 W/m°C wwww a = 0,13 x10 * m /s attachments Heisler diagrams for cylinder 1.0 F100 50 30 12 0.7 0.5 0.4 0.3 0.2 2.5 3.0 0.1 3 02 B hr 0.07 0.05 0.04 0.03 0,02 0.007 0.005 0.004 0.00 0.002 0.001 ! 2 3 468 101214 16 18 20 22 24 26 28 30 40 50 60 70 B0 90100 115 130 150200 300 kenle)= Fo 1.0 0.2 0.9 0.8 0.4 0.7 0.6 0.6 0.5 0.4 0.3 0.8 0.2 0.9 0.1 1.0 8.01 0.02 0.05 0.1 O.2 0.5 1.0 2 3 5 10 20 CA/hr)- Bi 50 100 T-T