The Effect of Admixture of Non-Evaporating Droplets on the Flow Structure and Adiabatic Wall Temperature in a Compressible Two-Phase Boundary Layer

Resumo

A mathematical model is constructed and numerical calculations of the problem of a highspeed longitudinal steady flow of a viscous heat conducting gas with an admixture of liquid droplets over a thermally insulated flat plate are performed. The droplet temperature is assumed to differ from that of the carrier gas. The range of flow parameters is considered, in which the droplet evaporation can be neglected but the temperature of droplets can vary significantly within the boundary layer. The mathematical model of two-phase boundary layer is modified taking into account the temperature nonuniformity inside the droplets. This required, along with solving the macroscopic equations of the two-fluid model, to find a solution of the heat conduction equation inside the droplets. On the basis of parametric calculations, the flow regimes with the formation of a liquid film due to droplet deposition on the wall are investigated. The similarity parameters are found and a range of governing parameters is determined in which, due to the heat exchange with the liquid phase in the boundary layer, a noticeable decrease in the adiabatic-wall temperature is manifested even at very small initial concentrations of the droplets.