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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 397 records · Page 22

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DOE OSTI2021

Effects of turbulence-radiation coupling in pressurized oxy-combustion

Concerns over climate change have led to numerous efforts in developing low-carbon energy technologies. Pressurized oxy-combustion (POC) is a promising candidate to reduce carbon emission in power generation. Due to the strong impact of pressure on thermal radiation, heat transfer in POC differs significantly from the situation of conventional atmospheric pressure combustion. Thus thermal radiation in POC needs to be investigated to aid new combustor development. The present computational work is a step in this direction, initiating a systematic analysis of thermal radiation and heat transfer in a pilot-scale POC combustor, which has been developed at Washington University in St. Louis (WUSTL). In a POC process, pulverized coal is burned under elevated pressure and O2-CO2 environment. While most previous computational works on flame radiation focused on atmospheric pressure condition, this work considered a pressurized flame. Specifically, a 15-bar POC combustor of power 50 kW is modeled employing the Ansys FLUENT commercial platform, using both Reynolds-averaged Navier-Stokes (RANS) modeling and large-eddy simulation (LES). A recently published and validated global radiation model is used to predict the radiative property of the flue gas. The discrete ordinates (DO) radiation model is chosen to solve the radiative transport equation. Incident radiation on the walls of the combustor is identified and investigated. It is revealed that for this pilot-scale, pressurized combustor, thermal radiation exhibits similar patterns in the RANS and LES models. However, the magnitudes of radiation are different in both models, presumably because interactions between radiation and turbulence are embedded in the LES model but not in the RANS model. This difference thereby underlines the major goal of this research: investigating the impact of such turbulence-to-radiation coupling on thermal radiation in a pilot-scale POC setting. Most previous studies on turbulence-to-radiation interactions focused on bench-scale, atmospheric pressure flames. This work is the first effort to extend this study to a pilot-scale, pressurized flame.

Li, Lei↗

NASA NTRS1973

The effect of angle of attach on the buckling of Mars entry aeroshells

The buckling modes of four optimized Mars entry aeroshell configurations at angle-of-attack loadings have been calculated. The analysis is based on experimental pressure distributions and was performed with the aid of a buckling digital computer program which treats general asymmetric linearized prebuckling states of branched shells of revolution. Only zero and first harmonic pressure components are treated, these being constructed from windward and leeward meridian pressure data at a mach number of 4.63. The results showed a rather small effect of the unsymmetrical pressure component on buckling for angles of attack up to 15 deg. Comparison of the results for the 120 deg cones to previous results indicates that the common procedure of basing the design on a symmetrized pressure distribution of the windward meridian is a conservative approach.

Cohen, G. A.↗

NASA NTRS1973

Digital image processing for information extraction.

The modern digital computer has made practical image processing techniques for handling nonlinear operations in both the geometrical and the intensity domains, various types of nonuniform noise cleanup, and the numerical analysis of pictures. An initial requirement is that a number of anomalies caused by the camera (e.g., geometric distortion, MTF roll-off, vignetting, and nonuniform intensity response) must be taken into account or removed to avoid their interference with the information extraction process. Examples illustrating these operations are discussed along with computer techniques used to emphasize details, perform analyses, classify materials by multivariate analysis, detect temporal differences, and aid in human interpretation of photos.

Billingsley, F. C.↗

NASA NTRS1983

Advanced earth observation spacecraft computer-aided design software: Technical, user and programmer guide

The IDEAS computer of NASA is a tool for interactive preliminary design and analysis of LSS (Large Space System). Nine analysis modules were either modified or created. These modules include the capabilities of automatic model generation, model mass properties calculation, model area calculation, nonkinematic deployment modeling, rigid-body controls analysis, RF performance prediction, subsystem properties definition, and EOS science sensor selection. For each module, a section is provided that contains technical information, user instructions, and programmer documentation.

Farrell, C. E.↗

NASA NTRS1986

Optimized Bolted Joint

Computer technique aids joint optimization. Load-sharing between fasteners in multirow bolted composite joints computed by nonlinear-analysis computer program. Input to analysis was load-deflection data from 180 specimens tested as part of program to develop technology of structural joints for advanced transport aircraft. Bolt design optimization technique applicable to major joints in composite materials for primary and secondary structures and generally applicable for metal joints as well.

Hart-Smith, L. J.↗

NASA NTRS1989

STRUTEX: A prototype knowledge-based system for initially configuring a structure to support point loads in two dimensions

Only recently have engineers begun making use of Artificial Intelligence (AI) tools in the area of conceptual design. To continue filling this void in the design process, a prototype knowledge-based system, called STRUTEX has been developed to initially configure a structure to support point loads in two dimensions. This prototype was developed for testing the application of AI tools to conceptual design as opposed to being a testbed for new methods for improving structural analysis and optimization. This system combines numerical and symbolic processing by the computer with interactive problem solving aided by the vision of the user. How the system is constructed to interact with the user is described. Of special interest is the information flow between the knowledge base and the data base under control of the algorithmic main program. Examples of computed and refined structures are presented during the explanation of the system.

Robers, James L.↗

NASA NTRS1991

Intelligent tutoring systems for systems engineering methodologies

The general goal is to provide the technology required to build systems that can provide intelligent tutoring in IDEF (Integrated Computer Aided Manufacturing Definition Method) modeling. The following subject areas are covered: intelligent tutoring systems for systems analysis methodologies; IDEF tutor architecture and components; developing cognitive skills for IDEF modeling; experimental software; and PC based prototype.

Meyer, Richard J.↗

NASA NTRS1992

Accurate Inventories Of Irrigated Land

System for taking land-use inventories overcomes two problems in estimating extent of irrigated land: only small portion of large state surveyed in given year, and aerial photographs made on 1 day out of year do not provide adequate picture of areas growing more than one crop per year. Developed for state of California as guide to controlling, protecting, conserving, and distributing water within state. Adapted to any large area in which large amounts of irrigation water needed for agriculture. Combination of satellite images, aerial photography, and ground surveys yields data for computer analysis. Analyst also consults agricultural statistics, current farm reports, weather reports, and maps. These information sources aid in interpreting patterns, colors, textures, and shapes on Landsat-images.

Wall, S.↗

NASA NTRS1993

A pattern recognition system for locating small volvanoes in Magellan SAR images of Venus

The Magellan data set constitutes an example of the large volumes of data that today's instruments can collect, providing more detail of Venus than was previously available from Pioneer Venus, Venera 15/16, or ground-based radar observations put together. However, data analysis technology has not kept pace with data collection and storage technology. Due to the sheer size of the data, complete and comprehensive scientific analysis of such large volumes of image data is no longer feasible without the use of computational aids. Our progress towards developing a pattern recognition system for aiding in the detection and cataloging of small-scale natural features in large collections of images is reported. Combining classical image processing, machine learning, and a graphical user interface, the detection of the 'small-shield' volcanoes (less than 15km in diameter) that constitute the most abundant visible geologic feature in the more that 30,000 synthetic aperture radar (SAR) images of the surface of Venus are initially targeted. Our eventual goal is to provide a general, trainable tool for locating small-scale features where scientists specify what to look for simply by providing examples and attributes of interest to measure. This contrasts with the traditional approach of developing problem specific programs for detecting Specific patterns. The approach and initial results in the specific context of locating small volcanoes is reported. It is estimated, based on extrapolating from previous studies and knowledge of the underlying geologic processes, that there should be on the order of 10(exp 5) to 10(exp 6) of these volcanoes visible in the Magellan data. Identifying and studying these volcanoes is fundamental to a proper understanding of the geologic evolution of Venus. However, locating and parameterizing them in a manual manner is forbiddingly time-consuming. Hence, the development of techniques to partially automate this task were undertaken. The primary constraints for this particular problem are that the method must be reasonably robust and fast. Unlike most geological features, the small volcanoes of Venus can be ascribed to a basic process that produces features with a short list of readily defined characteristics differing significantly from other surface features on Venus. For pattern recognition purposes the relevant criteria include (1) a circular planimetric outline, (2) known diameter frequency distribution from preliminary studies, (3) a limited number of basic morphological shapes, and (4) the common occurrence of a single, circular summit pit at the center of the edifice.

Burl, M. C.↗

NASA NTRS1994

Human factors issues and approaches in the spatial layout of a space station control room, including the use of virtual reality as a design analysis tool

Human Factors Engineering support was provided for the 30% design review of the late Space Station Freedom Payload Control Area (PCA). The PCA was to be the payload operations control room, analogous to the Spacelab Payload Operations Control Center (POCC). This effort began with a systematic collection and refinement of the relevant requirements driving the spatial layout of the consoles and PCA. This information was used as input for specialized human factors analytical tools and techniques in the design and design analysis activities. Design concepts and configuration options were developed and reviewed using sketches, 2-D Computer-Aided Design (CAD) drawings, and immersive Virtual Reality (VR) mockups.

Hale, Joseph P., II↗

NASA NTRS1998

EDCATS: An Evaluation Tool

The purpose of this research is to explore the development of Marshall Space Flight Center Unique Programs. These academic tools provide the Education Program Office with important information from the Education Computer Aided Tracking System (EDCATS). This system is equipped to provide on-line data entry, evaluation, analysis, and report generation, with full archiving for all phases of the evaluation process. Another purpose is to develop reports and data that is tailored to Marshall Space Flight Center Unique Programs. It also attempts to acquire knowledge on how, why, and where information is derived. As a result, a user will be better prepared to decide which available tool is the most feasible for their reports.

Heard, Pamala D.↗

NASA NTRS2002

A Thermal Management Systems Model for the NASA GTX RBCC Concept

The Vehicle Integrated Thermal Management Analysis Code (VITMAC) was further developed to aid the analysis, design, and optimization of propellant and thermal management concepts for advanced propulsion systems. The computational tool is based on engineering level principles and models. A graphical user interface (GUI) provides a simple and straightforward method to assess and evaluate multiple concepts before undertaking more rigorous analysis of candidate systems. The tool incorporates the Chemical Equilibrium and Applications (CEA) program and the RJPA code to permit heat transfer analysis of both rocket and air breathing propulsion systems. Key parts of the code have been validated with experimental data. The tool was specifically tailored to analyze rocket-based combined-cycle (RBCC) propulsion systems being considered for space transportation applications. This report describes the computational tool and its development and verification for NASA GTX RBCC propulsion system applications.

Traci, Richard M.↗

NASA NTRS1995

SRM Internal Flow Tests and Computational Fluid Dynamic Analysis: Cold Flow Analyses and CFD Analysis Capability Development - Volume 4

An evaluation of the effect of model inlet air temperature drift during a test run was performed to aid in the decision on the need for and/or the schedule for including heaters in the SRMAFTE. The Sverdrup acceptance test data was used to determine the drift in air temperature during runs over the entire range of delivered flow rates and pressures. The effect of this temperature drift on the model Reynolds number was also calculated. It was concluded from this study that a 2% change in absolute temperature during a test run could be adequately accounted for by the data analysis program. A handout package of these results was prepared and presented to ED35 management.

Source record↗

NASA NTRS1988

Computer-Aided Design Of Turbine Blades And Vanes

Quasi-three-dimensional method for determining aerothermodynamic configuration of turbine uses computer-interactive analysis and design and computer-interactive graphics. Design procedure executed rapidly so designer easily repeats it to arrive at best performance, size, structural integrity, and engine life. Sequence of events in aerothermodynamic analysis and design starts with engine-balance equations and ends with boundary-layer analysis and viscous-flow calculations. Analysis-and-design procedure interactive and iterative throughout.

Hsu, Wayne Q.↗

NASA NTRS1984

Computer-aided controllability assessment of generic manned Space Station concepts

NASA's Concept Development Group assessment methodology for the on-orbit rigid body controllability characteristics of each generic configuration proposed for the manned space station is presented; the preliminary results obtained represent the first step in the analysis of these eight configurations. Analytical computer models of each configuration were developed by means of the Interactive Design Evaluation of Advanced Spacecraft CAD system, which created three-dimensional geometry models of each configuration to establish dimensional requirements for module connectivity, payload accommodation, and Space Shuttle berthing; mass, center-of-gravity, inertia, and aerodynamic drag areas were then derived. Attention was also given to the preferred flight attitude of each station concept.

Ferebee, M. J.↗

NASA NTRS1982

Particle trajectory computer program for icing analysis of axisymmetric bodies

General aviation aircraft and helicopters exposed to an icing environment can accumulate ice resulting in a sharp increase in drag and reduction of maximum lift causing hazardous flight conditions. NASA Lewis Research Center (LeRC) is conducting a program to examine, with the aid of high-speed computer facilities, how the trajectories of particles contribute to the ice accumulation on airfoils and engine inlets. This study, as part of the NASA/LeRC research program, develops a computer program for the calculation of icing particle trajectories and impingement limits relative to axisymmetric bodies in the leeward-windward symmetry plane. The methodology employed in the current particle trajectory calculation is to integrate the governing equations of particle motion in a flow field computed by the Douglas axisymmetric potential flow program. The three-degrees-of-freedom (horizontal, vertical, and pitch) motion of the particle is considered. The particle is assumed to be acted upon by aerodynamic lift and drag forces, gravitational forces, and for nonspherical particles, aerodynamic moments. The particle momentum equation is integrated to determine the particle trajectory. Derivation of the governing equations and the method of their solution are described in Section 2.0. General features, as well as input/output instructions for the particle trajectory computer program, are described in Section 3.0. The details of the computer program are described in Section 4.0. Examples of the calculation of particle trajectories demonstrating application of the trajectory program to given axisymmetric inlet test cases are presented in Section 5.0. For the examples presented, the particles are treated as spherical water droplets. In Section 6.0, limitations of the program relative to excessive computer time and recommendations in this regard are discussed.

Frost, Walter↗

NASA NTRS1979

Paper simulation techniques in user requirements analysis for interactive computer systems

This paper describes the use of a technique called 'paper simulation' in the analysis of user requirements for interactive computer systems. In a paper simulation, the user solves problems with the aid of a 'computer', as in normal man-in-the-loop simulation. In this procedure, though, the computer does not exist, but is simulated by the experimenters. This allows simulated problem solving early in the design effort, and allows the properties and degree of structure of the system and its dialogue to be varied. The technique, and a method of analyzing the results, are illustrated with examples from a recent paper simulation exercise involving a Space Shuttle flight design task

Ramsey, H. R.↗

NASA NTRS1981

Integrated Analysis Capability pilot computer program

An integrated analysis capability (IAC) computer software package was developed for the design analysis and performance evaluation of large space systems. The IAC aids the user in coupling the required technical disciplines (initially structures, thermal and controls), providing analysis solution paths which reveal critical interactive effects in order to study loads, stability and mission performance. Existing technical software modules, having a wide existing user community, are combined with the interface software to bridge between the different technologies and mathematical modeling techniques. The package is supported by executive, data management and interactive graphics software, with primary development within the superminicomputer environment.

Vos, R. G.↗