Performance Analysis of Microthrusters Based on Coupled Thermal-Fluid Modeling and Simulation

A. A. Alexeenko, D. A. Levin, D. A. Fedosov, S. F. Gimelshein, R. J. Collins
2005 Journal of Propulsion and Power  
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
more » ... nozzle 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. Nomenclature a = speed of sound c p = specific heat at constant pressure h = height of nozzle h = heat-conduction coefficient k = thermal conductivitẏ m = mass flow rate N = number of particles P = inlet-to-outlet pressure ratio p = pressure q a = conductive heat flux q c = convective heat flux q r = radiative heat flux R = gas constant Re = Reynolds number with respect to the throat dimension T = temperature u = X component of velocity v = Y component of velocity t = computational time step x = cell size ρ = density σ = accommodation coefficient τ λ = mean time between collisions τ res = mean residence time in a cell = domain of the finite element method (FEM) solution Subscripts o = stagnation w = wall
doi:10.2514/1.5354 fatcat:f3ukpxyaojb2xloeokxiqfx4ri