13.38 A row of regularly spaced, cylindrical heating ele- ments is used to maintain an insulated furnace wall at 500 K. The opposite wall is at a uniform temperature of 300 K. 20 mm Wall, 300 K 10 mm Heating element Insulated wall, 500 K The insulated wall experiences convection with air at 450 K and a convection coefficient of 200 W/m².K. Assuming the walls and elements are black, estimate the required operating temperature for the elements.

13.38 A row of regularly spaced, cylindrical heating ele- ments is used to maintain an insulated furnace wall at 500 K. The opposite wall is at a uniform temperature of 300 K. 20 mm Wall, 300 K 10 mm Heating element Insulated wall, 500 K The insulated wall experiences convection with air at 450 K and a convection coefficient of 200 W/m².K. Assuming the walls and elements are black, estimate the required operating temperature for the elements.

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

See similar textbooks

Similar questions

A furnace with an aperture of 30 mm diameter and emissive power of 4x10^5 W/m^2 is used to calibrate a heat flux gage having a sensitive area of 2x10^-5 m^2At what distance, measured along a normal from the aperture, should the gage be positioned to receive irradiation of 1000 W/m^2 ? If the gage is tilted off normal by 20^o what will be its irradiation?
13.60 A furnace is located next to a dense array of cryogenic fluid piping. The ice-covered piping approximates a plane surface with an average temperature of T, = 0°C and an emissivity of ɛ, = 0.6. The furnace wall has a temperature of T,= 200°C and an emissiv- ity of ɛ, = 0.9. To protect the refrigeration equipment and piping from excessive heat loading, reflective aluminum radiation shielding with an emissivity of E, = 0.1 is placed between the piping and the furnace wall, as shown in the schematic. Assume all surfaces are diffuse-gray. Dense piping Furnace wall Tf = 200°C, e = 0.9 array, T, = 0°C, = 0.6 Installation criterion TNS 30°C -Radiation shields, N €, = 0.1 If the temperature of the shield closest to the piping T,N must be less than 30°C, how many radiation shields, N, must be installed between the piping and the furnace wall?
Please explain with steps.
A drying oven consists of a long semicircular duct of diameter D=1 m. Materials to be dried cover the base of the oven while the wall is maintained at 1200 K. Length of the oven (into paper direction) is 1 m. Water coated material is maintained at 325 K. Assume both the wall and the material to be blackbodies. (1) What is heat transfer rate? (2) Given at temperature 325 K, water needs heat 2.378 × 106 J/kg in order to be dried (from liquid water to steam). How much water can be dried per second based on the heat transfer rate from (1)? T₁ = 1200 K T₂ = 325 K — D = 1 m D= m→
I need the answer quickly
2 parts ( C&D) Read and solve carefully please write clearly and box the final answer(s) label them Hint: Pay attention to numbers bolded
5. A horizontal uninsulated steam pipe passes through a large room whose wall and ambient air are at 300 K. The air in the room is quiescent. The pipe of 150-mm diameter has an emissivity of 0.85 and an outer surface temperature of 400 K. Calculate the heat loss per unit length from the pipe.
3. A star has a surface temperature of 5,500K. Determine the radiative heat transfer received by planet Z in Petawatts with diameter of 2100 km, temperature of surface of 300K and mean absorptivity of 0.8. Radiative energy loss due to radiation dispersion on outer space is 99%.
A glass window pane and a pyrex window pane are held together as shown below. Heat is flowing through the combination from the hot side to the cold side. The temperatures of the hot surface and the cold surface are shown, with the temperature of the surface between them. The glass pane has a thickness of 3.00 mm. Find the thickness of the pyrex pane. (The cross-sectional areas are not needed.) Thermal conductivity of glass kglass = 0.800 J/s-m-C° Thermal conductivity of pyrex: kpyrex = 1.15 J/s-m-C° pyrex glass heat heat 3.00 mm T, = 38 °c T3 = 20° c %3D T2 = 23.4°C
Compute the heat gain for a window facing southeast at 32° north latitude at 10 A.M. central daylight time on August 21. The window is regular double glass with a 13-mm air space. The glass and inside draperies have a combined shading coefficient of 0.45. The indoor design temperature is 25° C, and the outdoor tempera ture is 37°C. Window dimensions are 2 m wide and 1.5m high.
Example 7.9 The filament of a 75 W light bulb may be considered a black body radiating into a black enclosure at 70°C.The filament diameter is 0.10 mm and length is 50 mm. Considering the radiation, determine the filament temperature.
6.4 Two large diffuse parallel plates are maintained at temperatures T₁ = 1400 K and T₂ = 700 K. The plates are made from the same metal, and their spectral emissivities as a function of wavelength, &, are approximated as shown by two constant values joined by a linear decrease with wavelength. Compute the net radiant energy flux being transferred from plate 1 to plate 2. What is the energy flux if both plates are assumed gray with an approximate average emissiv- ity of 0.5 applied over the entire spectral range? 91 T₁ = 1400 K, Ex T₂ = 700 K, EX 92-91 0.85 Ex 0.15 0 Answer: q₁106,850 W/m²; 91.gray = 68,070 W/m². 2 λ (μm) 7