This experiment is conducted to determine the emissivity of a certain material. A longcylindrical rod of diameter D₁ = 0.01 m is coated with this new material and is placed in anevacuated long cylindrical enclosure of diameter D₂ = 0.1 m and emissivity 2 = 0.95, whichis cooled externally and maintained at a temperature of 200 K at all times. The rod isheated by passing the electric current through it. When steady operating conditions arereached, it is observed that the rod is dissipating electric power at a rate of 16 W per unit ofits length, and its surface temperature is 600 K. Based on these measurements, determinethe emissivity of the coating on the rod.The emissivity of the coating on the rod is 0.1165

Answered: Image /qna-images/answer/e847f912-a250-424b-85f8-2c15a1781d1e.jpg

cal rod of diameter D₁ = 0.01 m is coated with this new material and is placed in an ed long cylindrical enclosure of diameter D₂ = 0.1 m and emissivity 2 = 0.95, which d externally and maintained at a temperature of 200 K at all times. The rod is by passing the electric current through it. When steady operating conditions are I, it is observed that the rod is dissipating electric power at a rate of 16 W per unit of h, and its surface temperature is 600 K. Based on these measurements, determine ssivity of the coating on the rod. issivity of the coating on the rod is 0.1165 >

cal rod of diameter D₁ = 0.01 m is coated with this new material and is placed in an ed long cylindrical enclosure of diameter D₂ = 0.1 m and emissivity 2 = 0.95, which d externally and maintained at a temperature of 200 K at all times. The rod is by passing the electric current through it. When steady operating conditions are I, it is observed that the rod is dissipating electric power at a rate of 16 W per unit of h, and its surface temperature is 600 K. Based on these measurements, determine ssivity of the coating on the rod. issivity of the coating on the rod is 0.1165 >

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.

Chapter11: Heat Transfer By Radiation

Section: Chapter Questions

Problem 11.43P

See similar textbooks

Similar questions

Determine the total average hemispherical emissivity and the emissive power of a surface that has a spectral hemispherical emissivity of 0.8 at wavelengths less than 1.5m, 0.6 at wavelengths from 1.5to2.5m, and 0.4 at wavelengths longer than 2.5m. The surface temperature is 1111 K.
11.31 A large slab of steel 0.1 m thick contains a 0.1 -m-di- ameter circular hole whose axis is normal to the surface. Considering the sides of the hole to be black, specify the rate of radiative heat loss from the hole. The plate is at 811 K, and the surroundings are at 300 K.
Two large parallel plates with surface conditions approximating those of a blackbody are maintained at 816C and 260C, respectively. Determine the rate of heat transfer by radiation between the plates in W/m2 and the radiative heat transfer coefficient in W/m2K.
11.68 Two infinitely large, black, plane surfaces are 0.3 m apart, and the space between them is filled by an isothermal gas mixture at 811 K and atmospheric pressure. The gas mixture consists of by volume. If one of the surfaces is maintained at 278 K and the other at 1390 K, calculate (a) the effective emissivity of the gas at its temperature, (b) the effective absorptivity of the gas to radiation from the 1390 K surface, (c) the effective absorptivity of the gas to radiation from the 278 K surface, and (d) the net rate of heat transfer to the gas per square meter of surface area.
11.41 Determine the steady-state temperatures of two radiation shields placed in the evacuated space between two infinite planes at temperatures of 555 K and 278 K. The emissivity of all surfaces is 0.8.
Determine the rate of radiant heat emission in watts per square meter from a blackbody at (a) 15C, (b) 600C, and (c) 5700C.
1.28 The sun has a radius of and approximates a blackbody with a surface temperature of about 5800 K. Calculate the total rate of radiation from the sun and the emitted radiation flux per square meter of surface area.
Three thin sheets of polished aluminum are placed parallel to each other so that the distance between them is very small compared to the size of the sheets. If one of the outer sheets is at 280C and the other outer sheet is at 60C, calculate the temperature of the intermediate sheet and the net rate of heat flow by radiation. Convection can be ignored.