Numerical investigation of micropropulsion systems for CubeSats: Gas species and geometrical effects on nozzle performance

In the present investigation, a numerical investigation is conducted to investigate cold-gas micropropulsion devices for CubeSat orbital control. Different micronozzle geometry configurations and gas species are analyzed to assess their influence on the flowfield structure, surface properties, and microthruster performance parameters. Due to the small length scales, the Direct Simulation Monte Carlo (DSMC) method is used to simulate rarefied argon and nitrogen in rectangular and curved micronozzles. The results indicate that nitrogen gas leads to a 23% increase in specific impulse at a relatively insignificant thrust cost. On the other hand, the use of a curved geometry increases the specific impulse and thrust generated by 23% and 35%, respectively. The results indicate that using lighter gases for cold gas microthrusters increases the micropropulsion efficiency. In addition, curved geometries significantly improve the overall performance of such devices, in contrast to rectangular geometries. •Rarefied non-reacting gas flows inside microthrusters for CubeSat Applications.•Argon gas instead of nitrogen has a negligible effect on the thrust.•Curved-wall micronozzles presented an increased thrust and specific impulse.•The surface aerodynamic coefficients exhibited substantial dependence on geometry and surface smoothness.•Lighter gases enhance the efficiency of micronozzles with minimal compromise on thrust.