HEAT AND MASS-TRANSFER FROM A SUPERCRITICAL LOX SPRAY

The injection, evaporation and diffusion of liquid oxygen in a high pressure airstream in a parallel wall mixing channel is analyzed and computationally solved. The droplet evaporation in the supercritical environment is treated by a non-isothermal droplet heat transfer model which accounts for the finite thermal conductivity of oxygen droplets and the gas film. The non-ideal gas effects in the gas phase are modeled by the Redlich-Kwong equation of state. The mixture density and enthalpy are determined by applying the ideal-solution limit which is shown to be valid for the prevailing conditions. The coupled dynamics of droplet and gas phases is calculated by solving numerically the Navier-Stokes equations in two dimensions. The turbulence effects are modeled by a two equation (k-epsilon) model. The results show that the non-ideal gas behavior prevails over a large portion of the mixing channel. Furthermore, the injected liquid oxygen droplets achieve critical temperature very quickly, and as a result they evaporate in the vicinity of the injection point. The effects of injection angle on oxygen mixing characteristics is also investigated.