In: Mechanical Engineering
Consider the flow of a liquid metal past a flat plate (Pr << 1). We have shown that for a constant wall teemperature, T_o, the Nusselt number is given by Nu = 0.564*(Re^1/2)*(Pr^1/2). Show that if the surface is not a constant temperature, but is instead providing a constant heat flux, that the Nusselt number becomes Nu = 0.886*(Re^1/2)*(Pr^1/2). Start with the following expression for the temperature profile within a semi-infinite body with a constant heat flux boundary condition T - T_o = (q_s / k)[ ((4*alpha*t) / pi)^1/2 * exp(-x^2 / (4*alpha*t)) - x*erfc( x / (4*alpha*t)^1/2 ) ].