two 5 cm diameter, 15 cm long aluminum bars (k=176W/m(degrees Celsius)) with ground surfaces are pressed aganist each other with a oressure of 20 atm. The bars are enclosed in an insulation sleeve and, thus, heat transfer from the lateral surfaces is negligible. if the top and bottom surfaces of the two-bar system are maintained at temperatures of 150 degrees Celsius and 20 degrees Celsius, respectively, determine: a) the rate of heat transfer along the cylinders under steady conditions; b) the temperature drop at the interface

two 5 cm diameter, 15 cm long aluminum bars (k=176W/m(degrees Celsius)) with ground surfaces are pressed aganist each other with a oressure of 20 atm. The bars are enclosed in an insulation sleeve and, thus, heat transfer from the lateral surfaces is negligible. if the top and bottom surfaces of the two-bar system are maintained at temperatures of 150 degrees Celsius and 20 degrees Celsius, respectively, determine: a) the rate of heat transfer along the cylinders under steady conditions; b) the temperature drop at the interface

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 1.19P: 1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the...

See similar textbooks

Similar questions

2.55 A long, 1-cm-diameter electric copper cable is embedded in the center of a 25-cm-square concrete block. If the outside temperature of the concrete is 25oC and the rate of electrical energy dissipation in the cable is 150 W per meter length, determine temperatures at the outer surface and at the center of the cable.
A cooling system is to be designed for a food storage warehouse for keeping perishable foods cool prior to transportation to grocery stores. The warehouse has an effective surface area of 1860 m2 exposed to an ambient air temperature of 32C. The warehouse wall insulation (k=0.17W/(mK)) is 7.5 cm thick. Determine the rate at which heat must be removed (W) from the warehouse to maintain the food at 4C.
3.16 A large, 2.54-cm.-thick copper plate is placed between two air streams. The heat transfer coefficient on one side is and on the other side is . If the temperature of both streams is suddenly changed from 38°C to 93°C, determine how long it takes for the copper plate to reach a temperature of 82°C.
A horizontal, 3-mm-thick flat-copper plate, 1-m long and 0.5-m wide, is exposed in air at 27C to radiation from the sun. If the total rate of solar radiation absorbed is 300 W and the combined radiation and convection heat transfer coefficients on the upper and lower surfaces are 20 and 15W/m2K, respectively, determine the equilibrium temperature of the plate.
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.
1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the convection heat transfer coefficient between the outer surface of the container and the air is 6.8 , the temperature of the air is 27°C, and the temperature of the surface of the sphere is –183°C, determine the rate of heat transfer by convection.
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 5.0 -cm-diameter aluminum cylinder is maintained at a temperature of 50-C in a large room where the air and wall temperature are at 20-C. The surface emissivity of the aluminum may be taken as 0.8 and the heat-transfer coefficient equal 6.5 W/m. C, calcualate the total heat lost by the pipe per unit length. (Stefan - Boitzmann constant = 5.669 x 10)
A hot surface at 100 °C is to be cooled by attaching 3-cm-long, 0.25-cm-diameter aluminum pin fins to it, with a center-to-center distance of 0.6 cm, as shown in Fig. 2. The temperature of the surrounding medium is 30 °C, and the heat transfer coefficient on the surfaces is 35 W/m2 K. Determine: the rate of heat transfer from the surface for a 10-cm x 10-cm section of plate, the overall effectiveness of the fins. i ii 3 cm 0.6 cm 0.25 cm Fig. 2
A soil with thermal diffusivity 6X106 m2/s and thermal conductivity 30 w/m.K is initially at a uniform temperature of 35°C. Suddenly, the surface is exposed to a coolant at 15°C for which the convection heat transfer coefficient is 100 W/m2 .K. Determine temperatures at the surface and at a depth of 20 cm after 5 min have elapsed.
It is designed in such a way that the internal temperature of a commercial heat treatment furnace can reach up to 165 oC. All surfaces of the furnace consist of firebrick (10 cm), insulation material and sheet metal (3mm) from the inside out. Given that the outdoor temperature is 22 oC, the outer sheet will be allowed to go up to 35 oC, which is a temperature that will not be disturbed by hand contact. In this case, determine the insulation material thickness to be used. Insulation material thermal conductivity coefficient is 0.066 insulation W / m oC, 60 W / m oC for sheet metal and 115 W / m oC for firebrick. Indoor heat transfer coefficient will be accepted as 25 W / m2 oC and 12 W / m2 oC for outdoor environment.
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.