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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Rocket propulsion by thermonuclear micro-bombs ignited with intense relativistic electron beams.

Discussion of a method for the ignition of a thermonuclear microbomb by means of an intense relativistic electron beam with regard to its potential application to rocket propulsion. With such a system, exhaust velocities up to 1000 km/sec, corresponding to a specific impulse of 100,000 sec, seem to be within the realm of possibility. The rocket is propelled by a chain of thermonuclear microbombs exploded in a concave magnetic mirror produced by superconducting field coils. The magnetic pressure of the field reflects the fireball generated by the explosion. For the large capacitor bank required to generate the intense relativistic electron beam, a desirable lightweight design may be possible through use of ferroelectric materials. Because of the high cost of the T-D and He 3-D thermonuclear material, the system has to be optimized by minimizing the T-D and He 3-D consumption by a proper TD and He 3-D fuel to hydrogen propellant mass ratio, leading to a larger total system mass than would be absolutely necessary.

Winterberg, F.↗
NASA NTRS1972

Space shuttle orbiter reentry flow field and heating analysis

The reentry flow field and thermal environment around the straight wing shuttle orbiter vehicle were determined. Both rarefied and continuum flow fields and associated heating rates on various configurations representative of the orbiter at high angle of attack were calculated. Rarefied flow fields and heating rates were computed by the Monte Carlo direct simulation technique for altitudes above 82.3 km. Continuum inviscid flow fields were calculated by 2-D unsteady and 3-D steady finite difference/artificial viscosity methods and also by a 2-D shock layer analysis technique. Viscous flow fields and heating rates in the continuum regime were computed by a boundary layer integral matrix method for laminar flow and by an aerodynamic surface heating technique for turbulent flow. Shapes considered in the study included flat plates (representing the underside of the orbiter fuselage or the wing MAC), orbiter fuselage cross sections, orbiter wing airfoils, and 3-D orbiter configurations, all at high angle of attack (40 - 60 deg). The theoretical results showed good agreement with measured pressure and heat transfer data.

Rochelle, W. C.↗
NASA NTRS1975

PLANS: A finite element program for nonlinear analysis of structures. Volume 1: Theoretical manual

The PLANS system is described which is a finite element program for nonlinear analysis. The system represents a collection of special purpose computer programs each associated with a distinct physical problem class. Modules of PLANS specifically referenced and described in detail include: (1) REVBY, for the plastic analysis of bodies of revolution; (2) OUT-OF-PLANE, for the plastic analysis of 3-D built-up structures where membrane effects are predominant; (3) BEND, for the plastic analysis of built-up structures where bending and membrane effects are significant; (4) HEX, for the 3-D elastic-plastic analysis of general solids; and (5) OUT-OF-PLANE-MG, for material and geometrically nonlinear analysis of built-up structures. The SATELLITE program for data debugging and plotting of input geometries is also described. The theoretical foundations upon which the analysis is based are presented. Discussed are the form of the governing equations, the methods of solution, plasticity theories available, a general system description and flow of the programs, and the elements available for use.

Pifko, A.↗
NASA NTRS1964

Computer programs for spherical satellites

This paper describes briefly two rather specialized computer programs which solve for steady-state temperatures over a sphere. The first program deals with opaque surfaces and allows for skin conduction and black body internal radiation. This program differs from the conventional 3-D heat transfer programs in that it automatically subdivides the sphere into a specified number of nodes and computes for each node, surface area, conductances, radiation shape factors and incident solar flux. The second program allows for transmission through partially or fully transparent external surfaces and accounts for multiple diffuse reflections at the inner surfaces, but does not include conduction.

THERMAL ENVIRONMENT↗
NASA NTRS1971

Advances in cryogenic foam insulations.

Description of a discretely oriented thread-reinforced polyurethane foam thermal insulation system for liquid hydrogen fuel tanks. The 3-D foam and glass liner composite is designed to be adhesively bonded to the inside surface of the tank wall and to be in direct contact with liquid hydrogen. All elements of this insulation composite are capable of sustaining the loads and environmental conditions imposed by testing under simulated Space Shuttle vehicle requirements at temperatures between -423 and +350 F.

Lemons, C. R.↗
NASA NTRS1972

Reentry heating and flow fields for Space Shuttle Orbiter at high angle of attack.

Rarefied flow fields and heating rates are calculated by a Monte Carlo direct simulation technique for several shuttle orbiter configurations at angles of attack between 40 and 60 deg. Continuum inviscid flow fields are determined by 2-D unsteady and 3-D steady finite-difference/artificial viscosity techniques used in combination with a 2-D shock layer analysis method. Continuum viscous flow fields and heating rates are computed by a boundary-layer integral matrix technique and an aerodynamic heating method.

Rochelle, W. C.↗
NASA NTRS1973

Three-D multilateration: A precision geodetic measurement system

A technique of satellite geodesy for determining the relative three dimensional coordinates of ground stations within one centimeter over baselines of 20 to 10,000 kilometers is discussed. The system is referred to as 3-D Multilateration and has applications in earthquake hazard assessment, precision surveying, plate tectonics, and orbital mechanics. The accuracy is obtained by using pulsed lasers to obtain simultaneous slant ranges between several ground stations and a moving retroreflector with known trajectory for aiming the lasers.

Escobal, P. R.↗
NASA NTRS1973

Nearly spherical constant-power detonation waves as driven by focused radiation.

Analysis is made of the flow within a 3-D spark created in a gas absorbing energy from a steady conical beam of radiation (typically obtained from an array of lasers) with nearly spherical symmetry. First-order deviations are represented by series of Legendre polynomials of the polar angle. Self-similarity is demonstrated. For harmonics 1 to 5 radial profiles of velocity components, density and pressure are presented. The linear perturbation scheme exhibits a singularity at the focus. This reflects the existence of a 'forbidden zone', as is shown by a study of the full non-linear flow equations.

George, Y. H.↗
NASA NTRS1974

Comparison of interference-free numerical results with sample experimental data for the AEDC wall-interference model at transonic and subsonic flow conditions

Numerical results obtained from two computer programs recently developed with NASA support and now available for use by others are compared with some sample experimental data taken on a rectangular-wing configuration in the AEDC 16-Foot Transonic Tunnel at transonic and subsonic flow conditions. This data was used in an AEDC investigation as reference data to deduce the tunnel-wall interference effects for corresponding data taken in a smaller tunnel. The comparisons were originally intended to see how well a current state-of-the-art transonic flow calculation for a simple 3-D wing agreed with data which was felt by experimentalists to be relatively interference-free. As a result of the discrepancies between the experimental data and computational results at the quoted angle of attack, it was then deduced from an approximate stress analysis that the sting had deflected appreciably. Thus, the comparisons themselves are not so meaningful, since the calculations must be repeated at the proper angle of attack. Of more importance, however, is a demonstration of the utility of currently available computational tools in the analysis and correlation of transonic experimental data.

Newman, P. A.↗
NASA NTRS1974

Quasi-three-dimensional flow solution by meridional plane analysis

A computer program has been developed to obtain subsonic or shockfree transonic, nonviscous flow analysis on the hub-shroud mid-channel flow surface of a turbomachine. The analysis may be for any annular passage, with or without blades. The blades may be fixed or rotating and may be twisted and leaned. The flow may be axial, radial or mixed. Blade surface velocities over the entire blade are approximated based on the rate of change of angular momentum. This gives a 3-D flow picture based on a 2-D analysis. The paper discusses the method used for the program and shows examples of the type of passages and blade rows which can be analyzed. Also, some numerical examples are given to show how the program can be used for practical assistance in design of blading, annular passages, and annular diffusers.

Katsanis, T.↗
NASA NTRS1975

An application of the Ogee tip

Wind tunnel tests show that the aerodynamic performance of a rectangular 3-D wing is increased by changing its tip to an ogee shape. Potential gains in both cruise and climb performances for a modified Beech Baron aircraft indicate that incremental changes in performance are on the order of the data scatter associated with applied flight test techniques.

Vogel, J. M.↗
NASA NTRS1975

INPUTB: A thermal/structural data interface program for 2-dimensional and 3-dimensional interpolation

A computer program (INPUTB) for interpolation in both space and time, and based on a linear interpolation scheme using simplex spatial regions is described. The program was developed to provide data interfacing between the output from thermal analyzers and the input to the BOPACE 3-D program. The INPUTB interpolator is of a general nature and could be used for other tasks. The INPUTB program utilizes temperature values which are given at some sequence of time for a list of strategically located thermal nodes. It operates on these values by performing a double interpolation to provide temperature values at another desired sequence of times for a list of structural nodes.

Vos, R. G.↗
NASA NTRS1976

Three-dimensional dynamical and chemical modelling of the upper atmosphere

Progress in coding a 3-D upper atmospheric model and in modeling the ozone perturbation resulting from the shuttle booster exhaust is reported. A time-dependent version of a 2-D model was studied and the sulfur cycle in the stratosphere was investigated. The role of meteorology in influencing stratospheric composition measurements was also studied.

Prinn, R. G.↗
NASA NTRS1976

Variational theorems for superimposed motions in elasticity, with application to beams

Variational theorems are presented for a theory of small motions superimposed on large static deformations and governing equations for prestressed beams on the basis of 3-D theory of elastodynamics. First, the principle of virtual work is modified through Friedrichs's transformation so as to describe the initial stress problem of elastodynamics. Next, the modified principle together with a chosen displacement field is used to derive a set of 1-D macroscopic governing equations of prestressed beams. The resulting equations describe all the types of superimposed motions in elastic beams, and they include all the effects of transverse shear and normal strains, and the rotatory inertia. The instability of the governing equations is discussed briefly.

Doekmeci, M. C.↗
NASA NTRS1976

A brief description of the Jameson-Caughey NYU transonic swept-wing computer program: FLO 22

A computer program for analyzing inviscid, isentropic, transonic flow past 3-D swept configurations is presented. Some basic aspects of the program are: (1) the free-stream Mach number is restricted only by the isentropic assumption; (2) weak shock waves are automatically located wherever they occur in the flow; (3) the finite-difference form of the full equation for the velocity potential is solved by the method of relaxation, after the flow exterior to the airfoil is mapped to the upper half plane; (4) the mapping procedure allows exact satisfaction of the boundary conditions and use of supersonic free stream velocities; (5) the finite difference operator is locally rotated in supersonic flow regions so as to properly account for the domain of dependence; and (6) the relaxation algorithm was stabilized using criteria from a time-like analogy.

Jameson, A.↗
NASA NTRS1991

Performance capabilities of a JPL dual-arm advanced teleoperation system

The system comprises: (1) two PUMA 560 robot arms, each equipped with the latest JPL developed smart hands which contain 3-D force/moment and grasp force sensors; (2) two general purpose force reflecting hand controllers; (3) a NS32016 microprocessors based distributed computing system together with JPL developed universal motor controllers; (4) graphics display of sensor data; (5) capabilities for time delay experiments; and (6) automatic data recording capabilities. Several different types of control modes are implemented on this system using different feedback control techniques. Some of the control modes and the related feedback control techniques are described, and the achievable control performance for tracking position and force trajectories are reported. The interaction between position and force trajectory tracking is illustrated. The best performance is obtained by using a novel, task space error feedback technique.

Szakaly, Z. F.↗