Improvements in Modeling 90 degree Bleed Holes for Supersonic Inlets

The modeling of porous bleed regions as boundary conditions in computational fluid dynamics (CFD) simulations of supersonic inlet flows has been improved through a scaling of sonic flow coefficient data for 90deg bleed holes. The scaling removed the Mach number as a factor in computing the sonic flow coefficient and allowed the data to be fitted with a quadratic equation, with the only factor being the ratio of the plenum static pressure to the surface static pressure. The implementation of the bleed model into the Wind-US CFD flow solver was simplified by no longer requiring the evaluation of the flow properties at the boundary-layer edge. The quadratic equation can be extrapolated to allow the modeling of small amounts of blowing, which can exist when recirculation of the bleed flow occurs within the bleed region. The improved accuracy of the bleed model was demonstrated through CFD simulations of bleed regions on a flat plate in supersonic flow with and without an impinging oblique shock. The bleed model demonstrated good agreement with experimental data and three-dimensional CFD simulations of bleed holes

Compressible gas properties of UF/sub 6/ for isentropic, normal shock, and oblique shock conditions

Isentropic, normal shock, and oblique shock tables are given for the real gas UF/sub 6/ for Mach numbers up to 22. An evaluation of the real gas effects is given. A computer program listing is included

Robust multi-disciplinary design and optimisation of a reusable launch vehicle

For various technical reasons, no fully reusable launch vehicle has ever been successfully constructed or operated. Nonetheless, a range of reusable hypersonic vehicles is currently being considered as a viable alternative to the expensive but more conventional expendable rocket systems that are currently being used to gain access to space. This paper presents a methodology that has been developed for the rapid and efficient preliminary design of such vehicles. The methodology that is presented uses multi-disciplinary design optimization coupled with an integrated set of reduced-order models to estimate the characteristics of the vehicle's aero-thermodynamic, propulsion, thermal protection and internal system architecture, as well as to estimate its overall mass. In the present work, the methodology has been applied to the multi-disciplinary modelling and optimization of a reusable hybrid rocket- and ramjet-powered launch vehicle during both the ascent and re-entry phases of its mission