Performance analysis of microthrusters based on coupled thermal-fluid modeling and simulation

Gas flow and performance characteristics of a high-temperature micro-electronically machined systems (MEMS)-based thruster are studied using a coupled thermal-fluid analysis. The material thermal response governed by the transient-heat-conduction equation is obtained by the finite element method. The low-Reynolds number gas flow in the microthruster is modeled by the direct simulation Monte Carlo approach. The effects of Reynolds number, thermal boundary conditions, and micronozzle height are considered in detail. The predicted thrust and mass-discharge coefficient of the three-dimensional microthruster under different flow conditions decrease with time as the viscous losses increase for higher wall temperatures.