Structure of a supersonic gas jet under conditions of developed condensation

Abstract

The method of flow visualization by electron-beam-induced radiation emission has been used to study the shape and structure of supersonic gas jets emitted into rarefied submerged space via sonic and supersonic nozzles from a forechamber at high pressure (stagnation pressure P0). It is established that the longitudinal size of a traditional primary supersonic jet increases with the stagnation pressure at fixed ratio P0/Ph, where Ph is the surrounding background gas pressure. This character of jet expansion via both sonic and supersonic nozzles is related to variation of the condensate fraction and average cluster size in the jet. Under the conditions of formation of large-size clusters in the supersonic jet of argon, a nontraditional gas jet shape with a long “wake” has been observed. No such secondary structure has been observed during the expansion of noncondensing helium and weakly condensing nitrogen. It is suggested that the formation of wake under conditions of developed condensation and significant rarefaction is related to the formation of a secondary clustered jet.