摘要
Micro-rockets for propulsion of small spacecrafts exhibit significant differences with regard to their macroscale counterparts,mainly caused by the role of the viscous dissipation and heat transfer processes in the micron-sized scale.The goal of this work is to simulate the transient operation of a micro-rocket to investigate the effects of viscous heating on the flow and performance for four configurations of the expanding gas and wafer material.The modelling follows a multiphysics approach that solves the fluid and solid regions fully coupled.A contin- uum-based description that incorporates the effects of gas rarefaction through the micro-nozzle,viscous dissipa- tion and heat transfer at the solid-gas interface is presented.Non-equilibrium is addressed with the implementa- tion of a 2nd-order slip-model for the velocity and temperature at the walls.The results stress that solid-fluid cou- pling exerts a strong influence on the flowfield and performance as well as the effect of the wafer during the first instants of the transient in micro-rockets made of low and high thermal conductivity materials.
基金
as part of the micropropulsion activities in the Small Satellites Programme,funded by the Spanish Ministry of Defence
