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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Hypersonic CFD applications for the National Aero-Space Plane

Design and analysis of the NASP depends heavily upon developing the critical technology areas that cover the entire engineering design of the vehicle. These areas include materials, structures, propulsion systems, propellants, integration of airframe and propulsion systems, controls, subsystems, and aerodynamics areas. Currently, verification of many of the classical engineering tools relies heavily on computational fluid dynamics. Advances are being made in the development of CFD codes to accomplish nose-to-tail analyses for hypersonic aircraft. Additional details involving the partial development, analysis, verification, and application of the CFL3D code and the SPARK combustor code are discussed. A nonequilibrium version of CFL3D that is presently being developed and tested is also described. Examples are given of portion calculations for research hypersonic aircraft geometries and comparisons with experiment data show good agreement.

Richardson, Pamela F.↗
NASA NTRS1991

National Aero-Space Plane (NASP) program

A program to develop the technology for reusable airbreathing hypersonic/transatmospheric vehicles is addressed. Information on the following topics is presented in viewgraph form: (1) the National Aerospace Plane (NASP) program schedule; (2) the NASP program organization; (3) competitive strategy; (4) propulsion options; (5) wind tunnel data available for NASP; (6) ground track of envelope expansion; and (7) altitude vs. Mach number. A NASP/Space Shuttle comparison, NASP configuration matrix, and the propulsion concept of a high speed scramjet are also briefly addressed.

Tank, Ming H.↗
NASA NTRS1991

An integrated aerodynamic/propulsion study for generic aero-space planes based on waverider concepts

Research efforts related to the development of a unified aerospace plane analysis based on waverider technology are summarized. Viscous effects on the forebodies of cone-derived waverider configurations were studied. A simple means for determining the average skin friction coefficient of laminar boundary layers was established. This was incorporated into a computer program that provides lift and drag coefficients and lift/drag ratio for on-design waveriders when the temperature and Reynolds number based on length are specified. An effort was made to carry out parabolized Navier-Stokes (PNS) calculations for cone-derived waveriders. When the viscous terms were turned off (in the Euler mode) computations for elliptic cone-derived waveriders could be carried out for a wide range of on-design and off-design situations. Work related to waveriders derived from power law shocks is described in some detail.

Emanuel, G.↗
NASA NTRS1991

The design of hypersonic waveriders for aero-assisted interplanetary trajectories

The aerodynamic performance of a vehicle designed to execute an aerogravity assisted maneuver, which combines a gravitational turn with a low-drag atmosphere pass, is examined. The advantage of the aerogravity assisted maneuver, as opposed to a more traditional gravity-assist trajectory, is that, through the use of a controlled atmospheric flight, nearly any deflection angle around a gravitating body can be realized. This holds the promise of providing extremely large values of Delta V. The success of such a maneuver depends on being able to design a vehicle which can execute sustained atmospheric flight at Mach numbers in the range of 50 - 100 with minimal drag losses. Some simple modeling is used to demonstrate design rules for the design of such vehicles, and to estimate the deterioration of their performance during the flight. Two sample aerogravity-assisted maneuvers are detailed, including a close solar approach requiring modest Delta V, and a sprint mission to Pluto.

Lewis, Mark J.↗
NASA NTRS1991

Optimal guidance of aero-assisted transfer vehicles based on matched asymptotic expansions

This paper addresses a number of issues related to the matched asymptotic expansions analysis of skip trajectories, or any class of problems that give rise to inner layers that are not associated directly with satisfying boundary conditions. The procedure for matching inner and outer solutions, and using the composite solution to satisfy boundary conditions is rigorously followed in developing a complete algebraic solution to the problem of inclination change with minimum energy loss. Repeated solution of these algebraic equations along the trajectory, treating each current state as an initial state, constitute a feedback guidance algorithm.

Calise, A. J.↗
NASA NTRS1991

The Effects of Manufacturing Tolerances on the Vibration of Aero-engine Rotor-damper Assemblies

A range of rotor assemblies incorporating one and two squeeze film dampers with various static misalignments is investigated. Waterfall diagrams are constructed which demonstrate the effects of such misalignment and damper support flexibility on the nature and severity of subsynchronous resonance and jump phenomena. Vibration signatures of similar rotor-bearing assemblies are shown to contrast strongly due to different accumulations of tolerances during manufacture, fitting, and operation.

Sykes, J. E. H.↗
NASA NTRS1991

Engineering method for aero-propulsive characteristics at hypersonic Mach numbers

An engineering method has been developed for the rapid analysis of external aerodynamics and propulsive performance characteristics of airbreathing vehicles at hypersonic Mach numbers. This method, based on the theory of characteristics, has been developed to analyze fuselage-wing body combinations and body flaps with blunt or sharp leading/trailing edges. Arbitrary ratio of specific heat for the flowing medium can be specified in the program. Furthermore, the capability exists in the code to compute the inviscid inlet mass capture and momentum flux. The method is under development for computations of pressure distribution, and flow characteristics in the inlet, along with the effect of viscosity. Correlative studies have been performed for representative hypersonic configurations using the current method. The results of these correlations for various aerodynamics parameters are encouraging.

Goradia, Suresh↗
NASA NTRS1992

Trajectories to the outer planets using aero-gravity assist flybys of Venus and Mars

The trajectory concept used here is to flyby Venus and then Mars with moderately high speeds expecting to use both gravity and aeroassisted (wave rider) turns in the atmospheres of the planets in order to form fast trajectories to the planets beyond Jupiter. The first part of the paper contains a description of the development of earth-Venus-Mars trajectories yielding the required speeds at Mars in the interval 2001 to 2015. The second part consists in identifying cases in which Mars is at the proper longitude for each target and obtaining trajectories. Trajectories to Saturn, Uranus, Neptune, and Pluto have been found.

Bender, David F.↗
NASA NTRS1992

Evaluation of an optimal guidance algorithm for aero-assisted orbit transfer

A detailed evaluation is performed of a guidance algorithm for aeroassisted orbit transfer that was developed earlier based on the method of matched asymptotic expansions. It is shown that, by exploiting the structure of the matched asymptotic expansion solution procedure, the original problem which requires the solution of a set of 20 implicit algebraic equations can be reduced to a problem of six implicit equations in six unknowns. The main contribution here is that it was possible to obtain a solution that is near optimal, requires a minimum of computation, and thus can be implemented in real time and on-board the vehicle. Guidance law implementation entails treating the current state as a new initial state and repetitively solving the matched asymptotic expansion problem to obtain the feedback controls.

Melamed, N.↗
NASA NTRS1992

Ka-band MMIC arrays for ACTS Aero Terminal Experiment

An antenna system consisting of three experimental Ka-band active arrays using GaAs MMIC devices at each radiating element for electronic beam steering and distributed power amplification is presented. The MMIC arrays are to be demonstrated in the ACTS Aeronautical Terminal Experiment, planned for early 1994. The experiment is outlined, with emphasis on a description of the antenna system. Attention is given to the way in which proof-of-concept MMIC arrays featuring three different state-of-the-art approaches to Ka-band MMIC insertion are being incorporated into an experimental aircraft terminal for the demonstration of an aircraft-to-satellite link, providing a basis for follow-on MMIC array development.

Raquet, C.↗
NASA NTRS1992

Aero-space plane figures of merit

The design environment of the aerospace plane is variable rich, intricately networked and sensitivity intensive. To achieve a viable design necessitates addressing three principal elements: knowledge of the 'figures of merit' and their relationships, the synthesis procedure, and the synergistic integration of advanced technologies across the discipline spectrum. This paper focuses on the 'figures of merit' that create the design of an aerospace plane.

Hunt, James L.↗
NASA NTRS1992

System safety activities supporting an aero-space plane ground support technology

An overview is presented of the specific system safety activities required to support the ground support technology program associated with the design of an aerospace plane. Safe zones must be assessed to ensure that explosive safety requirements are attained to protect the vehicle, personnel, and support and operational facilities. Attention is given to the specific and unique design requirements connected with the utilization of cryogenic fuels as they apply to the design and development of an aerospace plane.

Mattern, Steven F.↗
NASA NTRS1992

Perspective on the National Aero-space Plane program instrumentation development

Development of advanced measurement technology for the NASP program is reviewed. The technical need and the program commitment are discussed which are required to ensure that adequate and timely measurement capabilities are provided for ground and flight testing in the NASP program. Particular attention is given to an assessment of the current development status and a perspective on the features of the NASP program that contributed to the current state of instrumentation technology readiness.

Bogue, Rodney K.↗