Experimental and Numerical Modeling of Supersonic Jets Expanding into a Rarefied Medium Part 1: Noncondensing Flows

Abstract

This paper is the first part of a study aimed at developing methods for the experimental and numerical modeling of jet flows with significant rarefaction effects. The experimental measurements of flow parameters in jets expanding into a vacuum or highly rarefied medium are carried out on the modern gas-dynamic complex LEMPUS-2. The electron beam diagnostic (EBD) method was used for dimensional visualization of the flows and measurements of the absolute values of the local flow density. For the numerical simulation of a stationary axisymmetric nitrogen jet expanding from a sonic nozzle into a rarefied medium, a hybrid approach is employed: gas parameters in the dense flow region are determined using the solution of the Navier–Stokes equations, and in the rarefied flow region, using direct simulation Monte Carlo. The experimental and numerical methods are compared for this problem under conditions of no condensation. The results of the numerical calculations and experiments are compared with each other and with the published theoretical data. The close agreement of the results confirms the strong predictive ability of the methods used for the outflow of a noncondensable gas from sonic nozzles into a rarefied medium.