Aerothermodynamic Calculations on X-34 at Mach 6 Wind Tunnel Conditions


Book Description

The effects of Reynolds number and turbulence on surface heat-transfer rates are numerically investigated for a 0.015 scale X-34 vehicle at wind tunnel conditions. Laminar heating rates, non-dimensionalized by Fay-Riddell stagnation heating, do not change appreciably with an order of magnitude variation in Reynolds number. Modeling a turbulent versus laminar boundary layer at the same Reynolds number increases the windside heating by a factor of four, portions on the leeside by a factor of two, and causes a 30 percent increase in wing leading edge heating. A discrepancy between laminar and turbulent heating trends on the windside centerline is explained by the presence of attached windside vortices in the laminar solutions, structures that are inhibited by the turbulence modeling. Wood, William A. Langley Research Center NASA/TM-1999-208998, NAS 1.15:208998, L-17794







Design Methodologies for Space Transportation Systems


Book Description

Annotation "Design Methodologies for Space Transportation Systems is a sequel to the author's earlier text, "Space Transportation: A Systems Approach to Analysis and Design. Both texts represent the most comprehensive exposition of the existing knowledge and practice in the design and project management of space transportation systems, and they reflect a wealth of experience by the author with the design and management of space systems. The text discusses new conceptual changes in the design philosophy away from multistage expendable vehicles to winged, reusable launch vehicles and presents an overview of the systems engineering and vehicle design process as well as systems trades and analysis. Individual chapters are devoted to specific disciplines such as aerodynamics, aerothermal analysis, structures, materials, propulsion, flight mechanics and trajectories, avionics and computers, and control systems. The final chapters deal with human factors, payload, launch and mission operations, safety, and mission assurance. The two texts by the author provide a valuable source of information for the space transportation community of designers, operators, and managers. A companion CD-ROM succinctly packages some oversized figures and tables, resources for systems engineering and launch ranges, and a compendium of software programs. The computer programs include the USAF AIRPLANE AND MISSILE DATCOM CODES (with extensive documentation); COSTMODL for software costing; OPGUID launch vehicle trajectory generator; SUPERFLO-a series of 11 programs intended for solving compressible flow problems in ducts and pipes found in industrial facilities; and a wealth of Microsoft Excel spreadsheet programs covering thedisciplines of statistics, vehicle trajectories, propulsion performance, math utilities,




Integrated Hypersonic Aerothermoelastic Methodology for Transatmospheric Vehicle (TAV)/thermal Protection System (TPS) Structural Design and Optimization


Book Description

The adaptation of ZONA unified hypersonic/supersonic method ZONA7U and its integration/development into a ZONA aerothermoelastic software system for transatmospheric vehicle (TAV)/thermal protection system (TPS) design/analysis was proven a successful tool through feasibility study with cases of a CKEM body, blunt cones, and a modeled X-34 wing body. Preceding the feasibility study, substantial effort was directed toward further development of a new code, ZSTREAM, and using it and ZABRO to replace the outdated modules in SHVD, thus to couple them with SHABP for aerothermoelastic applications. In the feasibility study, the cases are well validated with FD solutions. Next, computed heat rates by applying ZONA aerothermoelastic software to X-34 through two assigned hypersonic trajectories were shown and found to agree with those using MINIVER. A potential TPS design procedure was established using the obtained heat rates as an input to MINIVER, resulting in a minimum weight TPS per hot-wall consideration. With FEM/TRIM modules, ASTROS* yields the trim solution and stress distribution for a flexible X-34 at a typical trajectory joint, demonstrating the multifunctionality in MDO for the aerothermoelastic software.