EXPERIMENTAL STUDIES ON THE DYNAMICS AND EVAPORATION OF TANDEM LIQUID DROPLETS IN A HOT GAS-FLOW

Dynamics and evaporation of tandem droplets moving upward in a free convective thermal boundary layer were experimentally investigated. The free convective boundary layer was formed from a hot isothermal vertical plate which has a high wall-to-ambient temperature difference. The gas velocity and temperature profiles were numerically obtained using the variable gas property model, and the results were used to analyze the droplet dynamic behavior and vaporization process. The effects of droplet interaction in the streamwise direction and mass transfer on the drag coefficient were studied. In addition, the effects of droplet dynamics on droplet evaporation were investigated. The experimental parameters tested in this study were the initial droplet size, spacing between droplets, and liquid properties. New drag coefficients for various liquids and droplet spacings were obtained and applied to the vaporization process.