Influence of stagnation pressure on two-phase flow gasdynamics in supersonic micronozzles

Abstract

The paper presents the results of the parametric study of the formation of two-phase flows of supersonic underexpanded xenon jets flowing from a micronozzle. A mathematical model of a viscous, compressible, heat-conducting gas based on the classical Navier-Stokes equations and supplemented by the equations of state for a perfect gas and the equations of the formation and transport of a condensed phase, was used for the numerical study of the gas dynamics of supersonic jets. The problem was solved in an axisymmetric formulation. The obtained distributions of the main gas-dynamic quantities made it possible to describe the flow structure and estimate the shape and size of local flow zones at the stagnation pressure levels of 5, 10 and 20 bar. The parametric analysis aimed at assessing the effect of stagnation pressure on the location and size of condensation zones in the flow has shown that an increase in total pressure leads to a shift in the condensation onset point deeper into the nozzle. The shape of the region inside the nozzle is determined by the length and expansion ratio, taking into account the boundary layer near t he walls. Behind the nozzle, the two-phase flow is limited by the cold core zone of the jet, the transverse dimensions of which are weakly depend on the stagnation pressure.