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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

A viscous flow analysis of the tip vortex generation process

A viscous primary-secondary flow analysis designed for numerical solution by forward marching integration is applied to the tip vortex generation problem. Equations governing streamwise momentum, streamwise vorticity, and a gas law are solved in conjunction with equations governing scalar and vector surface potentials for the secondary velocities. The numerical method used combines a consistently split linearized block implicit (LBI) scheme for parabolic equations and a scalar iterative ADI scheme for elliptic equations. Computed results are presented for a wing of rectangular planform immersed in a high Reynolds number stream at 6 degrees incidence. The physical mechanism for generation of the tip vortex, as revealed by the analysis and computations, is discussed. Detailed flow results for the case of 6 degree incidence are included.

Shamroth, S. J.↗
NASA NTRS1979

Historical development of worldwide supersonic aircraft

Aerodynamic problems in the development of supersonic aircraft, their solutions, and innovative design features are presented. Studies of compressibility, introduction of jets, supersonic phenomena, transonic drag and lift, longitudinal and directional stability, dynamic pressure fields, and advent of the supersonic fighter are discussed. The flight research aircraft such as the Bell X-1 and the Douglas-558, the century series models, reconnaissance aircraft, the multimission tactical fighter, and the current generation fighters such as F-16 and F-18 are described. The SCAT program is considered, along with supersonic developments in Great Britain, France, and USSR. It is concluded that the sonic boom still appears to be an inherent problem of supersonic flight that particularly affects overland commercial flight, and efforts continue for increased efficiency for economic and performance gains and increased safety for military and civilian aircraft.

Spearman, M. L.↗
NASA NTRS1980

Space Shuttle Main Engine development /May 1980/

The Space Shuttle Main Engine is the most advanced liquid propellant rocket engine ever developed. During the last year, significant progess has been made toward the identification and solution of several design weaknesses. The initial two test series to certify the engine's readiness for manned flight have been completed, and additional test series are in progress. Operation of the total propulsion system has been demonstrated by a successful series of flight-simulation tests using the three-engine cluster Main Propulsion Test Article. The first set of flight engines has been acceptance tested for use in Shuttle Orbiter 102 (Columbia) for the first manned orbital flight in late 1980 or early 1981. Engine development is continuing with initial demonstrations of full-power level (109%) operation capability.

Sanchini, D. J.↗
NASA NTRS1981

Space Operations Center, shuttle interaction study, volume 1

The implication of using the Shuttle with the SOC, including constraints that the Shuttle places upon the SOC design is studied. The considerations involved in the use of the Shuttle as a part of the SOC concept, and the constraints to the SOC imposed by the Shuttle in its interactions with the SOC, and on the design or technical solutions which allow satisfactory accomplishment of the interactions are identified.

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NASA NTRS1981

Space Operations Center: Shuttle interaction study

The implication of using the Shuttle with the Space Operation Center (SOC), including constraints that the Shuttle will place upon the SOC design. The study identifies the considerations involved in the use of the Shuttle as a part of the SOC concept, and also identifies the constraints to the SOC imposed by the Shuttle in its interactions with the SOC, and on the design or technical solutions which allow satisfactory accomplishment of the interactions.

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NASA NTRS1981

Spaceborne precipitation radar

The performances and characteristics of a satelliteborne radar operating in the millimeter wavelength region of the spectrum with emphasis placed on the 35 and 94 GH3 frequency bands are discussed. It is concluded that millimetric wavelengths provide an acceptable solution for the design of satelliteborne active microwave equipment.

Eckerman, J.↗
NASA NTRS1985

Generalized formulation of a class of explicit and implicit TVD schemes

A one parameter family of second order explicit and implicit total variation diminishing (TVD) schemes is reformulated so that a simpler and wider group of limiters is included. The resulting scheme can be viewed as a symmetrical algorithm with a variety of numerical dissipation terms that are designed for weak solutions of hyperbolic problems. This is a generalization of Roe and Davis's recent works to a wider class of symmetric schemes other than Lax-Wendroff. The main properties of the present class of schemes are that they can be implicit, and when steady state calculations are sought, the numerical solution is independent of the time step.

Yee, H. C.↗
NASA NTRS1985

A rotating electrical transfer device

The design, development, and performance characteristics of two roll ring configurations - a roll ring being a device used in transferring electrical energy across a continuously rotating or oscillating interface through one or more flexible rolling contacts, or flexures are described. Emphasis is placed on the design problems and solutions encountered during development in the areas of flexure fatigue, contact electroplating, electrical noise, and control of interface geometry. Also, the present status of each configuration is summarized.

Porter, R. S.↗
NASA NTRS1985

Three dimensional aerodynamics of an annular cascade in a non-uniform inlet flow

Three-dimensional viscous and inviscid numerical analyses are currently being developed to predict the complex flow through turbomachine blade passages. To be of value to the designer, these numerical solutions must be evaluated and subsequent refinements directed by correlating predicted flow fields with data obtained from experiments which model the fundamental three-dimensional flow phenomena inherent in blade rows. This paper describes a series of experiments to provide such data. In particular, the effect of a potential and a rotational inlet flow field on the detailed three-dimensional aerodynamic performance of an extensively instrumented cambered airfoil cascade has been determined at two levels of aerodynamic loading. Data presented quantify the pressure and suction surface static pressure chordwise distributions on the hub, mean, and tip streamlines; the velocity distribution in the cascade aft-passage region; and the cascade exit region flow field. Appropriate data are correlated with predictions.

Manwaring, S. R.↗
NASA NTRS1986

An inverse method for subcritical flows

An exact method is presented for two-dimensional subsonic flow within the limitations of the tangent gas approximation. While Woods (1961) studied these equations and proposed iterative methods for the solution of both the iterative and inverse problems, the inverse method here presented is noniterative and exact. It is shown that the direct Euler solution over the designed airfoil is very close to the input speed distribution, and that the constraints necessitated by upstream condition and closure requirements are easily incorporated.

Daripa, P. K.↗
NASA NTRS1987

Phased array antenna for space shuttle orbiter

The National Aeronautics and Space Administration is developing a distributed phased array antenna at the Lyndon B. Johnson Space Center as a possible upgrade for the Space Shuttle Orbiter S-band phase modulation communications system. The antenna consists of an eight-element transmit section, eight-element receive section, and a single L-band receive element. The antenna design is constrained by the existing Orbiter system and space environment. The solution to the interface design problems led to an antenna system which provides improved link margins and yet supports previous operational configurations. This paper describes the system development, antenna hardware, and the interface consideration which led to the final design.

Davidson, Shayla E.↗
NASA NTRS1988

Assessment, development and application of combustor aerothermal models

The gas turbine combustion system design and development effort is an engineering exercise to obtain an acceptable solution to the conflicting design trade-offs between: combustion efficiency, gaseous emissions, smoke, ignition, restart, lean blowout, burner exit temperature quality, structural durability, and life cycle cost. For many years, these combustor design trade-offs have been carried out with the help of fundamental reasoning and extensive component and bench testing, backed by empirical and experience correlations. Recent advances in the capability of computational fluid dynamics (CFD) codes have led to their application to complex three-dimensional flows such as those in the gas turbine combustor. A number of US. Government and industry sponsored programs have made significant contributions to the formulation, development, and verification of an analytical combustor design methodology which will better define the aerothermal loads in a combustor, and be a valuable tool for design of future combustion systems. The contributions made by NASA Hot Section Technology (HOST) sponsored Aerothermal Modeling and supporting programs are described in this paper.

Aerothermal modeling↗
NASA NTRS1988

Assessment, development, and application of combustor aerothermal models

The gas turbine combustion system design and development effort is an engineering exercise to obtain an acceptable solution to the conflicting design trade-offs between combustion efficiency, gaseous emissions, smoke, ignition, restart, lean blowout, burner exit temperature quality, structural durability, and life cycle cost. For many years, these combustor design trade-offs have been carried out with the help of fundamental reasoning and extensive component and bench testing, backed by empirical and experience correlations. Recent advances in the capability of computational fluid dynamcis codes have led to their application to complex 3-D flows such as those in the gas turbine combustor. A number of U.S. Government and industry sponsored programs have made significant contributions to the formulation, development, and verification of an analytical combustor design methodology which will better define the aerothermal loads in a combustor, and be a valuable tool for design of future combustion systems. The contributions made by NASA Hot Section Technology (HOST) sponsored Aerothermal Modeling and supporting programs are described.

Holdeman, J. D.↗
NASA NTRS1989

Computing Optimal Multiarc Trajectories

Optimal Multi-Arc Trajectories (OMAT) computer program designed to calculate solution to optimal-trajectory problem in cases of low thrust-to-weight ratios. Developed for two-body exoatmospheric problem with three degrees of freedom in inverse-square force field. Offers two different options: impulsive changes in velocity and finite burns with low thrust-to-weight ratios. Two distinct solutions available from program: optimal multi-impulse (OMI) solution and optimal multiburn (OMB) solution. Two solutions obtained separately, or results of OMI solution used to guess unknown parameters of OMB solution. Written for DEC VAX-series computer. Written completely in FORTRAN 77.

Jezewski, Donald J.↗
NASA NTRS1989

Assessment, development, and application of combustor aerothermal models

The gas turbine combustion system design and development effort is an engineering exercise to obtain an acceptable solution to the conflicting design trade-offs between: combustion efficiency, gaseous emissions, smoke, ignition, restart, lean blowout, burner exit temperature quality, structural durability, and life cycle cost. For many years, these combustor design trade-offs have been carried out with the help of fundamental reasoning and extensive component and bench testing, backed by empirical and experience correlations. Recent advances in the capability of computational fluid dynamics (CFD) codes have led to their application to complex three-dimensional flows such as those in the gas turbine combustor. A number of U.S. Govern- ment and industry sponsored programs have made significant contributions to the formulation, development, and verification of an analytical combustor design methodology which will better define the aerothermal loads in a combustor, and be a valuable tool for design of future combustion systems. The contributions made by NASA Hot Section Technology (HOST) sponsored Aero- thermal Modeling and supporting programs are described in this paper

J D Holdeman↗
NASA NTRS1989

Design and Navier-Stokes analysis of hypersonic wind tunnel nozzles

Four hypersonic wind tunnel nozzles ranging in Mach number from 6 to 17 are designed with the method of characteristics and boundary layer approach (MOC/BL) and analyzed with a Navier-Stokes solver. Limitations of the MOC/BL approach when applied to thick high speed boundary layers with non-zero normal pressure gradients are investigated. Working gases include ideal air, thermally perfect nitrogen and virial CF4. Agreement between the design conditions and Navier-Stokes solutions for ideal air at Mach 6 is good. Thermally perfect nitrogen showed poor agreement at Mach 13.5 and Mach 17. Navier-Stokes solutions for CF4 are not obtained, but comparison of the effects of low gamma to those of high Mach number suggests that the Navier-Stokes solution would not compare well with design.

Benton, James R.↗
NASA NTRS1990

A unified Navier-Stokes flowfield and performance analysis of liquid rocket engines

To improve the current composite solutions in the design and analysis of liquid propulsive engines, a computational fluid dynamics model capable of calculating the nonreacting and reacting flows from the combustion chamber, through the nozzle to the external plume, was developed. The Space Shuttle Main Engine (SSME) fired at sea level, along with the flowfields of several other nozzles were investigated. The bell-shaped SSME nozzle was run at 100 percent power level at various flow conditions, the computed flow results and performance compared well with those of other standard codes and engine hot fire test data.

Wang, Ten-See↗
NASA NTRS1990

An unmanned probe to Pluto

Now that Voyager II has completed its grand tour of the solar system, all the planets in the solar system, with the exception of Pluto, have been studied. Even now, missions to return to Mercury, Venus, Mars Jupiter, and Saturn are currently flying or are planned. However, a mission to explore Pluto is not, at the present time, being considered seriously. The design problem presented to the students was very general, i.e., design an unmanned mission to Pluto with a launch window constraint of the years 2000 to 2010. All other characteristics of the mission, such as mission type (flyby, orbiter, lander, penetrator), scientific objectives and payload, and the propulsion system were to be determined by the design teams. The design studies exposed several general problems to be solved. Due to the extreme distance to Pluto (and a corresponding travel time in the range of 10 to 25 years), the spacecraft had to be lighter and more robust than current spacecraft designs. In addition, advanced propulsion concepts had to be considered. These included the new generation of launch vehicles and upper stages and nuclear electric propulsion. The probe design offered an abundance of synthesis and analysis problems. These included sizing trade studies, selection of subsystem components, analysis of spacecraft dynamics, stability and control, structural design and material selection, trajectory design, and selection of scientific equipment. Since the characteristics of the mission, excluding the launch window, were to be determined by the design teams, the solutions varied widely.

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