A numerical study of the interfacial transport characteristics outside spheroidal bubbles and solids

In this paper, the interfacial transport characteristics to or from spheroidal bubbles are studied numerically and the results of numerical simulations are reported. The numerical modelling uses the SIMPLE method with a non-orthogonal, boundary fitted staggered grid. The aim of this paper is to provide an understanding of the interfacial transport characteristics of inviscid spheroidal bubbles, of different geometric parameters, rising in a stagnant hot or bi-solution liquid. The flow and concentration (or temperature) fields around bubbles and similarly sized rigid spheroids are computed. Detailed analyses of the pressure and vorticity distributions at surfaces of the inviscid spheroidal bubbles are made and compared with those of similar rigid spheroids. Drag coefficients for and wake lengths behind rigid spheroids and inviscid spheroidal bubbles are also presented. Local and mean Sherwood numbers and Nusselt numbers at bubble and rigid spheroid surfaces are compared, as well as their change with the Reynolds and Schmidt numbers and geometric parameters.