Viscous Effects on Biowaste Resistojet Nozzle Performance

Abstract

AND CARL R. HALBACHÂdvanced Rocket Technology (ARTCOR), Irvine, Calif.Viscous effects on the performance of biowaste resistojet microthrusters are calculated using Rae's numerica method for low-Reynolds number flow in a nozzle. Results are presented for a 25-mlb thruster suitable for space station attitude control using CO 2 , CH 4 , and H 2 O as propellants. Nozzle exit plane data (such as Mach number, velocity, and temperature profiles) useful for computations of plume contamination are also presented. The performance predictions are compared with experimental data which were available from laboratory firings of a 10-mlb thruster having a trumpet-shaped nozzle with CO 2 , CH 4 , H 2 O and H 2 as propellants. Nomenclature B= Reynolds number [see Eq.(specific enthalpy I sp = specific impulse M<£ = centerline Mach number MW = molecular weight m = mass flow rate P = power Pr = Prandtl number p = pressure R = universal gas constant r = radial coordinate, measured from nozzle axis r*,r w = nozzle throat, local nozzle radius T = temperature u = velocity x -z/r* z = axial coordinate, measured from nozzle throat y = specific-heat ratio A V = velocity increment 8 L = boundary-layer displacement thickness € = nozzle area ratio r] = r/r w or over all total power efficiency 61 = nozzle inlet convergence half angle (see Fig. 4) IJL = viscosity p = density co = exponent in the relation p.oc T 03 Subscript ( ) 0 = conditions in chamber, i.e., downstream end of heater Presented as Paper 72-450 at the

Medium power hydrogen arcjet performance

“…This type of dependence has been documented in previous tests of resistojets by numerous authors. [33][34][35][36][37] In an early test program involving small, evacuated-concentric tube type resistojets, the performance obtained with both hydrogen and ammonia was found to degrade significantly as the cell pressure increased from about 1.3 x 10 -5 to 10 kPa. Above 10 kPa the thrust appeared to be relatively independent of facility when both pressure-area and windage corrections were taken into account.…”