Development of an Upwind, Finite-Volume Code with Finite-Rate Chemistry

Abstract for the AIAA 29/h Thefmophysics Conference to be held on June 19-22, 1995 at San Diego, CA.Abstract Deadline: October 17, 1994. Computation of High-Speed Flow Fieldswith Multi-Dimensional Solid Heat Conduction ABSTRACTGregory A. Molvikt, Frank S. Milost, Thomas H. Squire" and Yih-Kano Chen"NASA Ames Research CenterMoffell Field, CA 94035In this paper, two methods are presented for thecomputation of high-speed flow fields thataccount for heat transfer to and within a vehicle.Emphasis is placed on the modeling of a materialcomposed of a diboride composile. The firstmethod couples a heat conduction computationwith a hypersonic boundary layer code throughmanual iteration. The second approach is a morecomprehensive method that employs a surfaceenergy balance to couple a new finite-volume,multi-dimensional, heat transfer code with ahypersonic computational fluid dynamic code.Generalized coordinate transformation areemployed in both the fluid and solid solvers, andthe flow lield solution and the vehicle thermalresponse are obtained simultaneously. Thisapproach allows the computation of time-accurate, transient behavior. A finite-volumephilosophy is maintained in both models toensure conservation of energy. Results areobtained for a simple conduction problem and ona blunt wedge geometry at hypersonic speeds.The final version of this paper will also include athree-dimensional transienl computation ol ahypersonic test problem.INTRODUCTIONThe TPS/structural weight ot hypersonic vehiclesand spacecralt is typically much larger than thepayload weight. For this reason any improvementin lhe fidelily of TPS sizing calculations which1 Senior Research Scientist, MCAT Institute,Member AIAA:1: Aerospace Engineer, Thermal Protection BranchResearch ScientJsls, ThermoscJences Insfitule atNASA Ames, Members AIAACopyright © by tile American lnstltutc of AeronauticsnndAsu'onautlcs, 1=1c.No copyrighl iS asserted in the UnitedS[:=tesunder Tide l? , U.S. Code. Tile U.S. Governmenth'=sa royalty-tree license to exercise all rights under thecopyright chimed herein for Government purposes. Allother rights are reserved by the copyright owner.leads Io an actual reduction in TPS weight has asignificant cost and feasibility impact on vehicledesign 1To reduce uncerlaintles in TPS sizing, efforts tocouple material response with CFD calculationshave proceeded rapidly in the last two years.Inilial work suggested the coupling of semi-analytic, approximate heat-conduction modelsand surface energy and mass balances with CFDcodes 1. Recent efforts have demonstrated thaifinite difference and finite volume thermal solverscan be used to calculate heat conduction into thevehicle TPS 2-3. This work presents the resultsof two analysis techniques that couple a flow fieldsolver with a thermal response model.The Thermal Protection Branch at NASA Ameshas developed diboride composites 't , whichwhen heated in air, develops a thin, adherent,high-melting-point oxide coating. These diboridecomposites are candidate materials for high heatflux areas ot hypersonic vehicles and spacecraftwhere other materials could not survive withoutsome type of active cooling. The primaryapplication of the diboride materials is as reusablenosetips and wing leading edges.To predict the performance of these materials inthis application, it is necessary to performcalculations which include multidimensional solidheat conduction coupled with the flow field. Thisis the focus of this paper.ANALYSIS TOOLSTwo methods of analysis are presented in thisstudy. The first technique manually couples aboundary layer code with a heat transfer code.The second technique is a more comprehensivemodel that uses a surface energy balance tocouple a hypersonic CFD code with a fullycompatible heat transfer code.