Twisted flow of a condensing gas mixture in a de Laval nozzle

Two-stage physico-mathematical model is proposed for investigation of a twisted gas mixture flow containing “passive” gas components, vapour of a condensable component and its droplets. At the first stage, spontaneous condensation is described in the frame of the four-moment set of equations; influence of the “passive” carrying gas mixture upon the condensation process is negligible. At the second stage, the above-obtained results serve as initial conditions for the further evolution of the multi-phase (multi-velocity and multi-temperature) flow. Parameters of the polidisperse mixture containing a finite number ($N$) of fractions are determined such as its moments coincide with those for the spontaneous droplets. As a result, gas-and-thermodynamics of the whole mixture turns to be described by a set of $N+1$ systems of equations, which take into consideration the exchange processes with mass, momentum and energy between phases. Numerical investigations are carried out by the Large Particles Method. Various cases of the prescribed radial distribution of the circumferential velocity component at the inlet of the channel with the varying cross-section area are investigated. Effects of polidispersity and centrifugal separation of condensed drops are discussed.