Modelling compressible gas flow near the nozzle of a gas atomiser using a new unified model

Abstract

In this paper, a unified numerical model is used to simulate the compressible gas flow, during the process of atomisation of liquid, near the atomiser nozzle in gas-only case studies. The flow of the under-expanded gas jets is studied, by analyzing the pressure field, density field and the spatial distribution of Mach number of the gas. The simulated predictions of gas status at the nozzle exit, the radial profile of Pitot pressure, aspiration pressure, and the spatial distribution of the density gradient, are compared with relevant experimental results and an analytical correlation, in order to validate and verify the application of this unified model in the numerical simulation of the gas dynamic behavior during gas atomisation. The simulation results show that the compressible gas flow near the nozzle of a discrete jet atomiser is different from that in a typical annular slit atomiser. Unlike existing models, this new formulation has the potential to be used in future to simulate the simultaneous flow of compressible gas and a weakly compressible liquid metal stream.