Plume Interactions of Multiple Jets Expanding into Vacuum: Experimental and Numerical Investigation

The main objective of this work is to examine the impac.1 of jet interactions in arrays of micropropulsion devices on thrust performance. Rarefied flow of nitrogen and helium from a single orifice and orifice arrays into vacuum was studied experimentally and numerically. The chamber pressure was changed in the range from 10 milli-torr to 40 torr, the orifice diameter was 1 mm, and the center-to-center distance between orifices varied from 1.5 to 4 orifice diameters. The direct simulation Monte Carlo (DSMC) method was used in all computatioli Good agreement between the experimental and nurrierical mass flow and thrust values was observed. A large impact of gas back flow was predicted numerically for m infinite array of orifices, that resulted in a specific ~mpulse increase of up to 20 percent.