Heat transfer 5 نقاط A plane wall (k = 45 W/m.K). 10 cm thick, has heat...
265 A person is found dead at 5 p.m. in a room where temperature is 20°C. The (1 temperature of the body is measured to be 25°C when found, and the heat transfer coefficient is estimated to be 8 W/m2.K. Modelling the human body a 30 cm diameter, 1.70 m long cylinder.calculate actual time in hours) of death of the person. Take thermophysical properties of the body :k = 6.08 * W/m.K, p = 900 kg/m3,C = 4000 J/kg.K إجابت...
Heat transfer question. A large wall made of 10-cm-thick solid brick (k = 0.8 W/m.K, p 2000 kg/m3, and p 800 J/kg.K) is originally at a uniform temperature of 30°C. The wall is adiabatic (well insulated) on one side as shown in the figure. The other surface is suddenly exposed to convection air flow at 10°C, resulting in a heat transfer coefficient h=40W/m2.K. Fluid (4.1) Determine the temperature of both surfaces Gr 0 and x 10 cm) after 5 hr...
The upper surface of a 60-cm-thick solid plate (k = 237 W/m.K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the 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. (T1+T) The thermal conductivity of water at the film temperature of Tf =(60°C + 20°C)/2 = 40°C is kfluid = 0.631 W/m.K. = 2 1. value: 3.00...
Heat Transfer -A wall 20 cm thick is to be constructed from material that has an average thermal conductivity of 2 W/m C. The wall is to be insulated with 5cm material having an average thermal conductivity of 0.5W/m C. Assuming that the inner and outer surface temperatures of the insulated wall are 200 and 20°C, calculate the heat transfer per unit area and the intermediate Temperature between the insulation and the wall.
The upper surface of a 60-cm-thick solid plate (k = 237 W/m.K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the 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/ mK. (T..+) The thermal conductivity of water at the film temperature of T, = =(60°C + 20°C)/2 = 40°C is kfluid = 0.631 W/mK. 1. value...
A concrete wall of a house is 45 cm thick and has a surface area 20m x 5 m. The inside temperature of the wall is 47 °C and the outside air temperature is 14 °C. Thermal conductivity of the concrete wall is 0.8 W/mK. Calculate the heat transfer rate through the wall by conduction and its thermal resistance.
For such aircraft application (Figure 3), a wall is made from insulation material (k-0.030 W/m.K) and the insulation material is mounted between four layers of carbon steel (2 mm thickness), the carbon layers are separated by a 2 mm air gap (kair-0.025 W/mK). Figure 3, the thermal conductivity of the carbon steel is (k-15.5 W/m.K). The temperature inside the wall is maintained at 6 °C. The environmental temperature is 24°C. The engineer would like to avoid condensation occurring at outer...
The heat generation rate in a plane wall of 0.24 m thickness is 0.4 MW/m3 . The wall is exposed on both sides to convection at 30°C. (a) Determine and compare the maximum temperatures for k = 25, k = 50, k = 200 and k = 410 W/mK assuming h = 250 W/m2K. (b) Determine and compare the maximum temperature for h = 50, 250, 500 and 1000 W/m2K with k = 25 W/mK.
Question 1: Your bear cooler is made of 20-mm-thick polystyrene (k = 0.021 W/m.K) and has interior dimensions of 0.5 mx0.3 m X 0.3 m. If you fill the inside with an ice-water mixture (so the temperature is maintained at 4°C) and leave the cooler on the porch on hot summer day (ambient temperature of 30°C ), what is the heat flux through the container wall? Assume negligible heat gain through the base of the cooler. You may have to...
A planar wall is composed of two materials, wall 1 has a uniform heat generation of 1.5 x 106 W/m3 and a thermal conductivity of 60 Wm.Κ. Wall 2 has no heat generation and thermal resistance of 150 W/m.K. The inner surface of Wall 1 is well insulated, while the outer surface of Wall 2 is exposed to 30°C fluld. The temperature of the wall surface exposed to the fluid is most nearly 00 heat flow fluid at 30°C h...