Bebang owns a 130-mm-thick concrete brick table top that has an area of 10,000,000 mm? and a 0.70-cm-thick glass plate has an area of 20,000 cm?. Assuming the same temperature difference across each, what is the ratio of the rate of heat conduction through the plate with respect to the rate of heat conduction through the tabe top? Use Table 10.1 (given below) for the value of Thermal Conductivity k. Table 10.1 Thermet Conductivities of Common Substances Values cre gnen for tenperatures near O C. Substance Thermal Conductivity k (Wim O Damond 2000 Siver 420 Copper Gold 315 Aluminum 220 Steel iron 80 Steel (stainless) 14 kce 2.2 Glass (average) 0.84 Concvte trick Water 0.6 Fatty tiszue (without ticod) 0.2 Asbestos Placterboard 0.16 Wood 0.00-0.16 Snow (dry) a.10 Cork 0.042 Glass wool 0042 Wool 0.04 Down feathers 0025 Air 0023 Polystyrene foam a010

Bebang owns a 130-mm-thick concrete brick table top that has an area of 10,000,000 mm? and a 0.70-cm-thick glass plate has an area of 20,000 cm?. Assuming the same temperature difference across each, what is the ratio of the rate of heat conduction through the plate with respect to the rate of heat conduction through the tabe top? Use Table 10.1 (given below) for the value of Thermal Conductivity k. Table 10.1 Thermet Conductivities of Common Substances Values cre gnen for tenperatures near O C. Substance Thermal Conductivity k (Wim O Damond 2000 Siver 420 Copper Gold 315 Aluminum 220 Steel iron 80 Steel (stainless) 14 kce 2.2 Glass (average) 0.84 Concvte trick Water 0.6 Fatty tiszue (without ticod) 0.2 Asbestos Placterboard 0.16 Wood 0.00-0.16 Snow (dry) a.10 Cork 0.042 Glass wool 0042 Wool 0.04 Down feathers 0025 Air 0023 Polystyrene foam a010

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 2.29P: 2.29 In a cylindrical fuel rod of a nuclear reactor, heat is generated internally according to the...

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Similar questions

One end of a 0.3-m-long steel rod is connected to a wall at 204C. The other end is connected to a wall that is maintained at 93C. Air is blown across the rod so that a heat transfer coefficient of 17W/m2 K is maintained over the entire surface. If the diameter of the rod is 5 cm and the temperature of the air is 38C, what is the net rate of heat loss to the air?
Both ends of a 0.6-cm copper U-shaped rod are rigidly affixed to a vertical wall as shown in the accompanying sketch. The temperature of the wall is maintained at 93C. The developed length of the rod is 0.6 m, and it is exposed to air at 38C. The combined radiation and convection heat transfer coefficient for this system is 34W/m2K. (a) Calculate the temperature of the midpoint of the rod. (b) What will the rate of heat transfer from the rod be?
The handle of a ladle used for pouring molten lead is 30 cm long. Originally the handle was made of 1.9cm1.25cm mild steel bar stock. To reduce the grip temperature, it is proposed to form the handle of tubing 0.15 cm thick to the same rectangular shape. If the average heat transfer coefficient over the handle surface is 14 W/m K, estimate the reduction of the temperature at the grip in air at 21C.
2.43 A turbine blade 6.3 cm long, with cross-sectional area and perimeter , is made of stainless steel . The temperature of the root, , is . The blade is exposed to a hot gas at , and the heat transfer coefficient is K. Determine the temperature of the blade tip and the rate of heat flow at the root of the blade. Assume that the tip is insulated.
Determine the rate of heat transfer per meter length from a 5-cm-OD pipe at 150C placed eccentrically within a larger cylinder of 85 magnesia wool as shown in the sketch. The outside diameter of the larger cylinder is 15 cm and the surface temperature is 50C.
A section of a composite wall with the dimensions shown below has uniform temperatures of 200C and 50C over the left and right surfaces, respectively. If the thermal conductivities of the wall materials are: kA=70W/mK,kB=60W/mK, kC=40W/mK, and kD=20W/mK, determine the rate of heat transfer through this section of the wall and the temperatures at the interfaces.
2.42 A circumferential fin of rectangular cross section, 3.7-cm OD and 0.3 cm thick, surrounds a 2.5-cm- diameter tube as shown below. The fin is constructed of mild steel. Air blowing over the fin produces a heat transfer coefficient of K. If the temperatures of the base of the fin and the air are and , respectively, calculate the heat transfer rate from the fin.
3.10 A spherical shell satellite (3-m-OD, 1.25-cm-thick stainless steel walls) re-enters the atmosphere from outer space. If its original temperature is 38°C, the effective average temperature of the atmosphere is 1093°C, and the effective heat transfer coefficient is , estimate the temperature of the shell after reentry, assuming the time of reentry is 10 min and the interior of the shell is evacuated.
2.29 In a cylindrical fuel rod of a nuclear reactor, heat is generated internally according to the equation where = local rate of heat generation per unit volume at r = outside radius = rate of heat generation per unit volume at the centerline Calculate the temperature drop from the centerline to the surface for a 2.5-cm-diameter rod having a thermal conductivity of if the rate of heat removal from its surface is 1.6 .
A 0.6-cm diameter mild steel rod at 38C is suddenly immersed in a liquid at 93C with hc=110W/m2K. Determine the time required for the rod to warm to 88C.