A numerical study on the transient heat transfer from a sphere at high Reynolds and Peclet numbers

The transient heat transfer rate from a particle depends on the flow field as well as the temperature field developed around the particle. The parameters that determine these two fields are the Reynolds number and the Peclet number. A numerical study has been performed in order to determine the transient heat transfer from a spherical particle in terms of both of these parameters. The governing equations of the problem are made dimensionless and are solved by using the stream function-vorticity formulation. The solution of the equations is achieved by using a stretched coordinate system and a tri-diagonal matrix algorithm. Good agreement of the numerical results was observed with previous studies on drag coefficients as well as with analytical and asymptotic expressions derived in the past. The results show a strong dependence of the rate of heat transfer on the Reynolds number, when the Peclet and Reynolds numbers are higher than one.