An initially cold T1(t = 0), pure aluminum spherical particle is rolling over a hot surface of temperature Ts at a constant speed ub and is heated through a contact conduction resistance Rk,c. This is shown in Figure Pr. 3.70.
(a) Draw the thermal circuit diagram.
(b) Is the assumption of a uniform temperature valid? Use Rk,1 = 1/(4πD1k1) for the internal conduction resistance.
(c) Determine the length L the ball has to travel before its temperature reaches Tf . Assume that the contact conduction is the only surface heat transfer (surfaceconvection and radiation heat transfer are assumed negligible).