(B) In order to measure the convection heat transfer coefficients one of the common methodsinvolve bonding one surface of a thin metallic foil to an insulating material and exposing the othersurface to the fluid flow conditions of interest.T, hFoil (Pelec T)Foam Insulation (k)Figure1: Heat transfer directionBy passing an electric current through the foil, heat is dissipated uniformly within the foil and thecorresponding flux (P elec) may be inferred from related voltage and current measurements.Consider conditions for which T0 = Tb = 25°C, Pelec = 2000 W/m2, L = 7 mm, and k = 0.05W/m.K.(1) With water flow over the surface, the foil temperature measurement yields Ts = 30°C. Determinethe convection heat transfer coefficient for both cases below. The foil has an emissivity of 0.15 andis exposed to large surroundings at 25°C.(2) On the other hand, if air flows over the surface and the temperature measurement yields Ts =120°C, how the convection heat transfer coefficient will be different?

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(B) In order to measure the convection heat transfer coefficients one of the common methods involve bonding one surface of a thin metallic foil to an insulating material and exposing the other surface to the fluid flow conditions of interest.

(B) In order to measure the convection heat transfer coefficients one of the common methods involve bonding one surface of a thin metallic foil to an insulating material and exposing the other surface to the fluid flow conditions of interest.

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.

Chapter8: Natural Convection

Section: Chapter Questions

Problem 8.50P

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