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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

A PCM/forced convection conjugate transient analysis of energy storage systems with annular and countercurrent flows

Latent heat energy storage systems with both annular and countercurrent flows are modeled numerically. The change of phase of the phase-change material (PCM) and the transient forced convective heat transfer for the transfer fluid are solved simultaneously as a conjugate problem. A parametric study and a system optimization are conducted. It is found that the energy storage system with the countercurrent flow is an efficient way to absorb heat energy in a short period for pulsed power load space applications.

Cao, Y.↗
NASA NTRS1990

Multi-disciplinary optimization of aeroservoelastic systems

Efficient analytical and computational tools for simultaneous optimal design of the structural and control components of aeroservoelastic systems are presented. The optimization objective is to achieve aircraft performance requirements and sufficient flutter and control stability margins with a minimal weight penalty and without violating the design constraints. Analytical sensitivity derivatives facilitate an efficient optimization process which allows a relatively large number of design variables. Standard finite element and unsteady aerodynamic routines are used to construct a modal data base. Minimum State aerodynamic approximations and dynamic residualization methods are used to construct a high accuracy, low order aeroservoelastic model. Sensitivity derivatives of flutter dynamic pressure, control stability margins and control effectiveness with respect to structural and control design variables are presented. The performance requirements are utilized by equality constraints which affect the sensitivity derivatives. A gradient-based optimization algorithm is used to minimize an overall cost function. A realistic numerical example of a composite wing with four controls is used to demonstrate the modeling technique, the optimization process, and their accuracy and efficiency.

Karpel, Mordechay↗
NASA NTRS1997

Standardized Methods for Electronic Shearography

Research was conducted in development of operating procedures and standard methods to evaluate fiber reinforced composite materials, bonded or sprayed insulation, coatings, and laminated structures with MSFC electronic shearography systems. Optimal operating procedures were developed for the Pratt and Whitney Electronic Holography/Shearography Inspection System (EH/SIS) operating in shearography mode, as well as the Laser Technology, Inc. (LTI) SC-4000 and Ettemeyer SHS-94 ISTRA shearography systems. Operating practices for exciting the components being inspected were studied, including optimal methods for transient heating with heat lamps and other methods as appropriate to enhance inspection capability.

Lansing, Matthew D.↗
NASA NTRS1967

Saturn V launch vehicle systems analysis application.

Systems analysis applied to identification of Saturn V launch vehicle support system requirements and establishment of baseline logic for vehicle prelaunch processing simulation and systems optimization

SYSTEMS ANALYSIS↗
NASA NTRS1984

Design of vibration isolation systems using multiobjective optimization techniques

The design of vibration isolation systems is considered using multicriteria optimization techniques. The integrated values of the square of the force transmitted to the main mass and the square of the relative displacement between the main mass and the base are taken as the performance indices. The design of a three degrees-of-freedom isolation system with an exponentially decaying type of base disturbance is considered for illustration. Numerical results are obtained using the global criterion, utility function, bounded objective, lexicographic, goal programming, goal attainment and game theory methods. It is found that the game theory approach is superior in finding a better optimum solution with proper balance of the various objective functions.

Rao, S. S.↗
NASA NTRS1980

Systems analysis - Key to NASA's data system planning

Critical steps in the systems analysis process for NASA's data system planning are: (1) compilation of future user/mission requirements, (2) development of alternative overall data system concepts which satisfy requirements, (3) assessment of future development and availability of data system technology, and (4) cost/performance tradeoff studies of the alternative concepts for systems optimization. Tasks within the NEEDS (NASA End-to-End Data System) Program, which correspond to the critical steps in this systems analysis process are examined.

Nelson, R. W.↗
NASA NTRS1990

A comparison of energy conversion systems for meeting the power requirements of manned rover for Mars missions

Several types of conversion systems of interest for a nuclear Mars manned application are examined, including: free-piston Stirling engines (FPSE), He/Xe closed Brayton cycle (CBC), CO2 open Brayton, and SiGe/GaP thermoelectric systems. Optimization studies were conducted to determine the impact of the conversion system on the overall mass of the nuclear power system and the mobility power requirement of the rover vehicle. The results of an analysis of a manned Mars rover equipped with a nuclear reactor power system show that the free-piston Stirling engine and the He/Xe closed Brayton cycle are the best available options for minimizing the overall mass and electric power requirements of the rover vehicle. While the current development of Brayton technology is further advanced than that of FPSE, the FPSE could provide approximately 13.5 percent lower mass than the He/Xe closed Brayton system. Results show that a specific mass of 160 is achievable with FPSE, for which the mass of the radiation shield (2.8 tons) is about half that for He/Xe CBC (5 tons).

El-Genk, Mohamed S.↗
NASA NTRS2002

Remote Sensing Requirements Development: A Simulation-Based Approach

Earth science research and application requirements for multispectral data have often been driven by currently available remote sensing technology. Few parametric studies exist that specify data required for certain applications. Consequently, data requirements are often defined based on the best data available or on what has worked successfully in the past. Since properties such as spatial resolution, swath width, spectral bands, signal-to-noise ratio (SNR), data quantization and band-to-band registration drive sensor platform and spacecraft system architecture and cost, analysis of these criteria is important to optimize system design objectively. Remote sensing data requirements are also linked to calibration and characterization methods. Parameters such as spatial resolution, radiometric accuracy and geopositional accuracy affect the complexity and cost of calibration methods. However, few studies have quantified the true accuracies required for specific problems. As calibration methods and standards are proposed, it is important that they be tied to well-known data requirements. The Application Research Toolbox (ART) developed at the John C. Stennis Space Center provides a simulation-based method for multispectral data requirements development. The ART produces simulated datasets from hyperspectral data through band synthesis. Parameters such as spectral band shape and width, SNR, data quantization, spatial resolution and band-to-band registration can be varied to create many different simulated data products. Simulated data utility can then be assessed for different applications so that requirements can be better understood.

Zanoni, Vicki↗
NASA NTRS1998

Aerospace Power Systems Design and Analysis (APSDA) Tool

The conceptual design of space and/or planetary electrical power systems has required considerable effort. Traditionally, in the early stages of the design cycle (conceptual design), the researchers have had to thoroughly study and analyze tradeoffs between system components, hardware architectures, and operating parameters (such as frequencies) to optimize system mass, efficiency, reliability, and cost. This process could take anywhere from several months to several years (as for the former Space Station Freedom), depending on the scale of the system. Although there are many sophisticated commercial software design tools for personal computers (PC's), none of them can support or provide total system design. To meet this need, researchers at the NASA Lewis Research Center cooperated with Professor George Kusic from the University of Pittsburgh to develop a new tool to help project managers and design engineers choose the best system parameters as quickly as possible in the early design stages (in days instead of months). It is called the Aerospace Power Systems Design and Analysis (APSDA) Tool. By using this tool, users can obtain desirable system design and operating parameters such as system weight, electrical distribution efficiency, bus power, and electrical load schedule. With APSDA, a large-scale specific power system was designed in a matter of days. It is an excellent tool to help designers make tradeoffs between system components, hardware architectures, and operation parameters in the early stages of the design cycle. user interface. It operates on any PC running the MS-DOS (Microsoft Corp.) operating system, version 5.0 or later. A color monitor (EGA or VGA) and two-button mouse are required. The APSDA tool was presented at the 30th Intersociety Energy Conversion Engineering Conference (IECEC) and is being beta tested at several NASA centers. Beta test packages are available for evaluation by contacting the author.

Truong, Long V.↗
NASA NTRS2010

Water Injection on Commercial Aircraft to Reduce Airport Nitrogen Oxides

The potential nitrogen oxide (NO(x) reductions, cost savings, and performance enhancements identified in these initial studies of waterinjection technology strongly suggest that it be further pursued. The potential for engine maintenance cost savings from this system should make it very attractive to airline operators and assure its implementation. Further system tradeoff studies and engine tests are needed to answer the optimal system design question. Namely, would a low-risk combustor injection system with 70- to 90-percent NO(x) reduction be preferable, or would a low-pressure compressor (LPC) misting system with only 50-percent NO(x) reduction but larger turbine inlet temperature reductions be preferable? The low-pressure compressor injection design and operability issues identified in the report need to be addressed because they might prevent implementation of the LPC type of water-misting system. If water-injection technology challenges are overcome, any of the systems studied would offer dramatic engine NO(x) reductions at the airport. Coupling this technology with future emissions-reduction technologies, such as fuel-cell auxiliary power units will allow the aviation sector to address the serious challenges of environmental stewardship, and NO(x) emissions will no longer be an issue at airports.

Daggett, David L.↗
NASA NTRS2020

Electric Aircraft Cooling with Bio-Inspired Exergy Management

Future air vehicles will increasingly incorporate electrical powertrains that require very tight system-level integration of power, propulsion, thermal, fault protection, and airframe technologies. This chapter provides an overview of a new category of thermal energy conversion technology and describes the development of the resulting Thermal Recovery Exergy Efficient System, TREES. TREES can be used to enable a fully solid-state integrated thermal and fault management electric aircraft protection system, while synergistically managing and recycling both the low-grade waste heat from electrical components and the high-grade waste heat from engine components. This is achieved with exergy amplification of the powertrain waste heat, a new class of fast flight-weight breakers, a new class of long variable-conductance heat pipes with multiple switchable condensers, a new class of turbofan-integrated heat exchangers, and a gradient-based powertrain system optimizer. This approach is like the human body’s thermal management system in which the heart, arteries, and veins are analogous to the turbofan, acoustic tubes, and heat pipes proposed herein.

Rodger W Dyson↗
NASA NTRS1980

Optimal regulation in systems with stochastic time sampling

An optimal control theory that accounts for stochastic variable time sampling in a distributed microprocessor based flight control system is presented. The theory is developed by using a linear process model for the airplane dynamics and the information distribution process is modeled as a variable time increment process where, at the time that information is supplied to the control effectors, the control effectors know the time of the next information update only in a stochastic sense. An optimal control problem is formulated and solved for the control law that minimizes the expected value of a quadratic cost function. The optimal cost obtained with a variable time increment Markov information update process where the control effectors know only the past information update intervals and the Markov transition mechanism is almost identical to that obtained with a known and uniform information update interval.

Montgomery, R. C.↗
NASA NTRS2014

Apparatus and Methods for Manipulation and Optimization of Biological Systems

The invention provides systems and methods for manipulating biological systems, for example to elicit a more desired biological response from a biological sample, such as a tissue, organ, and/or a cell. In one aspect, the invention operates by efficiently searching through a large parametric space of stimuli and system parameters to manipulate, control, and optimize the response of biological samples sustained in the system. In one aspect, the systems and methods of the invention use at least one optimization algorithm to modify the actuator's control inputs for stimulation, responsive to the sensor's output of response signals. The invention can be used, e.g., to optimize any biological system, e.g., bioreactors for proteins, and the like, small molecules, polysaccharides, lipids, and the like. Another use of the apparatus and methods includes is for the discovery of key parameters in complex biological systems.

Ho, Chih-Ming↗
NASA NTRS1969

Programmed schedule holds for improving launch vehicle holds

Baseline definition and system optimization are used for the analysis of programmed holds developed through prelaunch system analysis. Identification of design specifications for ground support equipment and maintenance concepts, and design specifications are used to describe the functional utilization of the overall flow process.

Gralow, F. H.↗
NASA NTRS1972

Quiet STOL propulsion session introductory remarks

Research activities, preliminary design activities, and system optimization studies in support of the development of advanced, quiet, STOL propulsion systems are discussed. Noise alleviation by means of controlling the source and by means of acoustical treatment receive considerable emphasis. A STOL airplane designed for a given payload has essentially double the installed thrust of a comparable CTOL airplane. Unless compensated for during the design process, this alone will tend to increase the source noise by 3 db. The propulsive lift introduces flap impingement noise or duct and flap scrubbing noise, noise sources not present in CTOL airplanes to any significant degree. These additional noise sources are illustrated. Depending on the specific configuration, this will tend to increase the noise by several db or more. Although the propulsive lift characteristics of STOL airplanes will tend to increase source noise significantly, the proximity of STOL airfields to populated areas leads to STOL noise objectives considerably lower than those currently applicable to CTOL airplanes.

Schroeder, R. W.↗
NASA NTRS1977

Active optics simulation system

Set of three major computer program packages aids design of mirror control system for large telescopes. It can be used to evaluate merit of particular active optics control system (or component subsystem); and once system configuration is chosen, it can be used as design aid to optimize system parameters.

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