Multi-Species Fluxes for the Parallel Quiet Direct Simulation (QDS) Method

Abstract

Fluxes of multiple species are implemented in the Quiet Direct Simulation (QDS) scheme for gas flows. Each molecular species streams independently. All species are brought to local equilibrium at the end of each time step. The multi species scheme is compared to DSMC simulation, on a test case of a Mach 20 flow of a xenon/helium mixture over a forward facing step. Depletion of the heavier species in the bow shock and the near-wall layer are seen. The multispecies QDS code is then used to model the flow in a pulsed-pressure chemical vapour deposition reactor set up for carbon film deposition. The injected gas is a mixture of methane and hydrogen. The temporal development of the spatial distribution of methane over the substrate is tracked.

Pulsed-Pressure MOCVD Science, Materials and Technology

“…Assuming a sticking coefficient of unity and a Monte Carlo simulation of the gas dynamics during the pump-down phase, the possibility of high precursor conversion efficiency was demonstrated (11). A new numerical method termed "Quiet Direct Simulation" has been developed to model the droplet evaporation and more complex internal geometries for new industrial-scale reactors (12).…”