Inviscid and Viscous Predictions for a E-beam Heated Hypersonic Wind-Tunnel (Invited)
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In previous work  we have developed an axisymmetric 2D simulation of a Mach 12, missile scale, hypersonic wind-tunnel based on energy addition from a high power e-beam source downstream of the throat. This simulation uses a tabulated equation of state (NIST 14) for air and includes a Monte Carlo simulation of 200,000, 3Mev, electrons which propagate upstream towards the throat and are confined by a magnetic field. They give their energy to the air through an increasing number of collisions as the density of the air increases. Surrounding this heated flow is a largely unheated outer flow that protects the wall from the heated core flow and shields it from direct heating by all but a very small percentage of scattered electrons. This initial work assumed that the flow is inviscid. Notwithstanding the large increase in total enthalpy due to the e-beam heating (a factor of approximately 3), the parameters required to achieve Mach 12, without forming shocks in the heat addition region and in the subsequent expansion, were found. In the work presented here we extend this simulation to include the effect of viscosity and thermal conductivity and in particular the turbulent transport in the boundary layer near the wall. In a companion paper (AIAA 2002-3128) we discuss the extensive theoretical and experimental work being done to validate the model at a unit Reynolds number of approximately 1010/m. The turbulent transport is modeled using the Baldwin-Lomax formulation with the inclusion of wall roughness based on the model of Rotta. In this paper we have used these models in Navier Stokes calculations to obtain preliminary results for the wall recovery temperature, the rate of heat transfer to an isothermal wall, particularly in the throat region, and to obtain the test section Mach number and velocity distributions. The effects of roughness on heat transfer and the test section Mach number profiles are being considered but are not included here. At the throat a recovery temperature of approximately 1640K is found and for a wall temperature of 1500K a heat transfer rate of approximately 49 kW/cm2is calculated. This suggests that film cooling of the throat region with an inert gas is likely to be needed. Notwithstanding the total length of the nozzle, it is found that the boundary layer heats most of the outer flow which, in the inviscid case, would condense but it does not have a significant effect on the 1m diameter Mach12 core flow. Results are also briefly reported on a 2Mev simulation with a revised thermodynamic path that eliminates the shock waves that were found in .
author list (cited authors)
Girgis, I. G., Brown, G. L., Miles, R. B., & Lipinski, R. J.
Girgis, I., Brown, G., Miles, R., & Lipinski, R.