Simulation of High-Speed Flow in μ-Rockets for Space Propulsion Applications

Summary

The simulation of micron-sized rockets for space propulsion requires the accurate modelling of the highly coupled physical processes that take place. The purpose of this investigation is the assessment of the continuum-based Navier–Stokes approach with slip boundary conditions in “large” MEMS, where slip-flow is expected to occur in the μ-nozzle. Non-equilibrium near the walls is addressed with the implementation of a 2nd-order slip-model for the velocity and temperature at the solid-gas interface, where thermal coupling is enforced. Initial validation with axisymmetric and three-dimensional DSMC data of μ-rockets is provided. Numerical results at operational flow conditions show that transitional flow is reached near the exit of the nozzle and that strong rarefaction occurs ahead the nozzle-lip and in the gas plume. The effects of viscous dissipation and heat transfer upon the flowfield and performance are discussed in detail.