HEAT AND MASS-TRANSFER FROM A FLAT-PLATE OF FINITE THICKNESS TO A BOUNDARY-LAYER FLOW WITH TRANSPIRATION

Cooling a flat plate by evaporation of a volatile liquid from the surf ace to a laminar boundary layer flow past the plate is theoretically a nalyzed, taking into account both injection effect due to the vaporiza tion and two-dimensional thermal conduction in the plate, with convect ive thermal-boundary condition on the other plate surface. The thermal effect of the volatile liquid supply to the plate is neglected and al l of the physical properties are assumed to be constant in spite of th e changes in concentration and temperature in the boundary layer. Repr esentative calculations were performed for air-water system with vario us thermal conditions of the plate and flow conditions. The temperatur e fields and distributions of the local Nusselt and Sherwood numbers a re estimated for a parallel flow case. The effects of parameters relat ed to the wall conduction on the injection parameter are discussed. Co mparison of results calculated for air-methanol and air-water systems shows that in the former case the injection gives more significant inf luence on the heat and mass transfer characteristics. (C) 1997 Elsevie r Science Ltd.