UNSTEADY CONJUGATE HEAT-TRANSFER ASSOCIATED WITH A TRANSLATING SPHERICAL DROPLET - A DIRECT NUMERICAL-SIMULATION

Thermal behavior of a liquid drop moving in an incompressible fluid of infinite extent is investigated numerically. Dynamical equations desc ribing the temporal evolution of the flow and temperature fields of di spersed and continuous phases are solved by a hybrid spectral scheme i n conjunction with the influence matrix technique to resolve the lack of vorticity boundary conditions. Both Chebyshev and Legendre polynomi als are employed to expand the flow variables and temperature in the r adial and angular directions, respectively. With the aid of the Galerk in and collocation methods, together with the first-order backward Eul er time differencing, the governing partial differential equations red uce to a nonlinear system of algebraic equations. Numerical results re veal a discrepancy between quasi-steady and fully transient analyses a t high Peclet numbers.