For the system outlined in Problem 2.11, determine an expression for the critical radius of the insulation in terms of the thermal conductivity of the insulation and the surface coefficient between the exterior surface of the insulation and the surrounding fluid. Assume that the temperature difference, R1, R2, the heat transfer coefficient on the interior, and the thermal conductivity of the material of the sphere between R1 and R2 are constant.GIVENAn insulated hollow sphereRadiiInner surface of the sphere = R1Outer surface of the sphere = R2Outer surface of the insulation = R3ASSUMPTIONSConstant temperature difference, radii, heat transfer coefficients, and thermal conductivitiesSteady stateprevails

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Sphere Mateklal - 12 TI Insulation