Substitution of Hot-Gas Lateral Jets by Cold-Gas Jets in Supersonic Flows

Abstract

The supersonic flow around a rocket piloted by thrusters has been investigated. Steady Reynolds-averaged Navier-Stokes computations and pressure measurements in a wind tunnel, using pressure taps and pressuresensitive paint, have been performed. For experimental investigations, real hot-gas thrusters have been replaced by cold-gas jets using a lower total pressure and a different gas. The uniqueness of this work involved calibrating those cold-gas thrusters in order to reproduce an aerodynamic interference very similar to the hot-gas jets case. This has been achieved by modifying the section ratio of the nozzles in order to control the wave celerity ratio between freestream and jet flows. A good agreement has been obtained between numerical simulations of hot-gas and cold-gas jets flows, as well as between computations and measurements of the pressure coefficient around the body in the wind tunnel. Thus, this method has provided a good approximation for the interaction between hot-gas jets and crossflow by using lower-pressure and lower-temperature jets.the body, m J = momentum flux similarity number JR = momentum flux ratio M = mass flux similarity number M th = thruster ejection Mach number M 1 = freestream Mach number NCR = nozzle celerity ratio NJR = nozzle momentum flux ratio NMR = nozzle mass flux ratio NPR = nozzle pressure ratio NrTR = nozzle temperature ratio P = pressure similarity number PR = total pressure ratio P j = nozzle exit static pressure, Pa P o , P 1 = freestream static pressure, Pa P t = total pressure, Pa P ti = thruster stagnation pressure, Pa Re D = diameter-based Reynolds number r th = specific thruster gas constant, J kg 1 K 1 r 1 = specific freestream gas constant, J kg 1 K 1 T = temperature similarity number T j = nozzle exit static temperature, K T t = total temperature, K T ti = thruster stagnation temperature, K T 1 = freestream static temperature, K U = velocity component along the x axis, m s 1 U o , U 1 = freestream velocity component along the x axis, m s 1 u f = friction velocity component along the x axis, m s 1 W = velocity component along the mean ejection direction, m s 1 W j = nozzle exit velocity component along the mean ejection direction, m s 1 x = horizontal coordinate along the body axis, m y = horizontal coordinate perpendicular to the body axis, m y = dimensionless wall distance z = vertical coordinate, m th = thruster gas isentropic coefficient 1= freestream gas isentropic coefficient = kinematic viscosity, m 2 s 1 = density, kg m 3 j = nozzle exit density, kg m 3 1 = freestream density, kg m 3 w = wall shear, Pa

Turbulence Model Effects on Cold-Gas Lateral Jet Interaction in a Supersonic Crossflow

“…Some data for the DLR model were obtained for a hot-gas jet [11], for which the model diameter was 70 mm but the jet nozzle diameter remained 4 mm. More recent results from some of the same authors included additional results from wind-tunnel investigations on hot-gas lateral jet ejection [14,15] and substitution of hot-gas lateral jets by cold-gas simulants in supersonic flow [16].…”

Effects of Turbulence Model on Prediction of Hot-Gas Lateral Jet Interaction in a Supersonic Crossflow

“…More recent results from these authors include additional results from wind tunnel investigations on hot-gas lateral jet ejection 11,12 and an experimental and computational study on the substitution of hot-gas lateral jets by cold-gas simulants in supersonic flow. 13 Hold et al 14 performed a computational investigation based on the experimental data of Stahl et al, 11 finding that it was necessary to use a realgas, nonreacting, multispecies-based solution to most accurately predict the missile surface pressures due to the JI. However, Hold et al 14 also found that an ideal-gas hot-air jet provided reasonable aerodynamic force and moment predictions compared with the multispecies hot-gas predictions.…”

Numerical Investigation of Jet Interaction for Missile with Continuous Type Side Jet Thruster

“…The understanding of the phenomena that occur with respect to the reaction control of missiles has matured [1,2]. But it is still difficult to predict precisely the aerodynamic jet interferences in order to evaluate jet thruster effectiveness, because of the difficulties in achieving similitude between a wind tunnel test and actual flight conditions [3][4][5]. With the advances in CFD technology and high performance computing, the CFD technique has come to play an important part in predicting jet interferences of lateral jets [5][6][7][8][9][10][11][12].…”