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 how field a s well as the temperature field developed around the particle. The paramete rs that determine these two fields are the Reynolds number and the Peclet n umber. A numerical study has been performed in order to determine the trans ient heat transfer from a spherical particle in terms of both of these para meters. The governing equations of the problem are made dimensionless and a re solved by using the stream function-vorticity formulation. The solution of the equations is achieved by using a stretched coordinate system and a t ri-diagonal matrix algorithm. Good agreement of the numerical results was o bserved with previous studies on drag coefficients as well as with analytic al and asymptotic expressions derived in the past. The results show a stron g dependence of the rate of heat transfer on the Reynolds number, when the Peclet and Reynolds numbers are higher than one. (C) 1999 Elsevier Science Ltd. All rights reserved.