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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 289 records · Page 16

Aircraft energy efficiency. Overview

Six advanced technology development projects that could cut fuel consumption of future civil air transports by as much as 50 percent are highlighted. These include improved engine components; better engine design; thin short blades for turboprop aircaft; using composite primary structures for weight reduction; the use of supercritical wings, higher aspect ratio, and winglets for improved aerodynamics; active controls; and laminar flow control. The time span of each of the six efforts and NASA's expected expenditures are also discussed.

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Research and Technology 1997

NASA Lewis Research Center is responsible for developing and transferring critical technologies that address national priorities in aeropropulsion and space applications in partnership with U.S. industries, universities, and Government institutions. As NASA s designated Lead Center for Aeropropulsion, our role is to develop, verify, and transfer aeropropulsion technologies to U.S. industry. As NASA s designated Center of Excellence in Turbomachinery, our role is to develop new and innovative turbomachinery technology to improve the reliability, performance, efficiency and affordability, capacity, and environmental compatibility of future aerospace vehicles. We also maintain a science and technology development role in aeropropulsion, communications, space power and onboard propulsion, and microgravity fluid physics and combustion. We are committed to enabling non-aerospace U.S. industries to benefit directly from the technologies developed through our programs to maximize the benefit to the Nation and the return on each taxpayer s investment. In addition, we are aggressively pursuing continuous improvement in our management and business practices and striving for diversity in our workforce as together we push the edge of technology in space and aeronautics. The Lewis Research Center is a unique facility located in an important geographical area, the southwest corner of Cleveland, Ohio. Situated on 350 acres of land adjacent to the Cleveland Hopkins International Airport, Lewis comprises more than 140 buildings that include 24 major facilities and over 500 specialized research and test facilities. Additional facilities are located at Plum Brook Station, which is about 50 miles west of Cleveland. Over 3700 people staff Lewis, including civil service employees and support service contractors. Over half of them are scientists and engineers, who plan, conduct or oversee, and report on our research tasks and projects. They are assisted by technical specialists, skilled workers, and an administrative staff. Our end product is knowledge. This report is designed to help us make this knowledge fully available to potential users the aircraft engine industry, the energy industry, the automotive industry, the aerospace industry, and others. It is organized so that a broad cross section of the community can readily use it. Each article begins with a short introductory paragraph that should prove to be a valuable tool for the layperson. These articles summarize the progress made during the year in various technical areas and portray the technical and administrative support associated with Lewis technology programs. We hope that the information is useful to all. If additional information is desired, readers are encouraged to contact the researchers identified in the articles and to visit Lewis on the World Wide Web (http://www.lerc.nasa.gov/). This document is available on the World Wide Web (http://www.lerc.nasa.gov/WWW/RT).

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Low NO(x) Combustor Development

The goal of these efforts was the development of an ultra-low emissions, lean-burn combustor for the High Speed Civil Transport. The HSCT Mach 2.4 FLADE C1 Cycle was selected as the baseline engine cycle. A preliminary compilation of performance requirements for the HSCT combustor system was developed. The emissions goals of the program, baseline engine cycle, and standard combustor performance requirements were considered in developing the compilation of performance requirements. Seven combustor system designs were developed. The development of these system designs was facilitated by the use of spreadsheet-type models which predicted performance of the combustor systems over the entire flight envelope of the HSCT. A chemical kinetic model was developed for an LPP combustor and employed to study NO(x) formation kinetics, and CO burnout. These predictions helped to define the combustor residence time. Five fuel-air mixer concepts were analyzed for use in the combustor system designs. One of the seven system designs, one using the Swirl-Jet and Cyclone Swirler fuel-air mixers, was selected for a preliminary mechanical design study.

Kastl, J. A.↗

Overview of NASA's advanced high temperature engine materials technology program

NASA's 'HITEMP' program has been charged with development of propulsion systems technologies for next-generation civil and military aircraft, stressing high-temperature/low-density composites. These encompass polymer-matrix composites for fans, ducts, and compressor cases, and intermetallic and metallic alloy matrix composites for applications in turbine disks, blades, and vanes, and ceramic matrix composites for combustors and turbines. An overview is presented of program concerns and achievements to date.

Ginty, Carol A.↗

Aeronautical research in the United States: Challenges for the 1990's

New opportunities for greater performance civil air transportation aircraft derive from the continuing advancements in the aeronautical disciplines: advancements in aerodynamics, structures and materials, propulsion, and flight control technologies. These opportunities impact future subsonic transports, high speed civil transports, and hypersonic vehicles. There are, however, new constraints within which progress will be made, including stringent environmental constraints on engine emissions and noise, old and new safety constraints on operations (especially in severe weather), aging airframes, and changing transportation marketplace demands affecting all of these vehicle classes. Some of the NASA aeronautical research programs will be discussed in four areas: (1) advanced subsonic airplanes; (2) next generation high speed civil transport aircraft (SST's); (3) high performance military aircraft; and (4) next century hypersonic vehicles. This presentation overviews the exciting progress which is possible in aeronautics during the 1990's.

Holmes, Bruce J.↗

Initial characterization of a modular heat exchanger with an integral heat pipe

As part of the Civil Space Technology Initiative (CSTI) Advanced Technology program, a conceptual design of the Stirling space engine (SSE) was generated. The overall goal of the CSTI high capacity power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The free-piston Stirling engine (FPSE) was chosen as the growth option in the CSTI program. A major goal during the conceptual design of the SSE was to reduce the number of critical joints. One area of concern was the heat exchanger assemblies that typically have the majority of critical joints. The solution proposed in the SSE conceptual design used 40 modular heat exchangers. Each module has its own integral heat pipe to transport heat from the heat source to the engine. A demonstration of the modular concept was undertaken before committing to the detailed design of the SSE heat exchangers. An existing FPSE was modified as a test bed for modular heat exchanger evaluation. The engine incorporated three heat exchanger modules, each having a sodium filled heat pipe. The thermal loading of these modules was intended to be similar to the conditions projected for the SSE modules. The engine was assembled and tests are underway. The design and fabrication of the heat exchanger modules and the engine used for these tests were described. Evaluation of the individual heat pipes before installation in the engine is described. The initial test results with the modules in operation on the engine were presented. Future tests involving the engine were outlined.

Schreiber, Jeffrey G.↗

The 1989 high-speed civil transport studies

The results of the Douglas Aircraft Company system studies related to high speed civil transports (HSCT) are discussed. The studies were conducted to assess the environmental compatibility of a high speed civil transport at a design Mach number of 3.2. Sonic boom minimization, external noise, and engine emissions were assessed together with the effect of the laminar flow control (LFC) technology on vehicle gross weight. The general results indicated that a sonic boom loudness level of 90-PLdB at Mach 3.2 may not be achievable for a practical design; the high flow engine cycle concept shows promise of achieving the sideline FAR Part 36 noise limit, but may not achieve the aircraft range design goal of 6,500 nautical miles; the rich burn/quick quench (RB/QQ) combustor concept shows promise for achieving low EINO sub x levels when combined with a premixed pilot stage/advanced technology, high power stage duct burner in the Pratt and Whitney variable steam control engine (VSCE); and full chord wing LFC has significant performance and economic advantages relative to the turbulent wing baseline.

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Study and Sub-System Optimization of Propulsion and Drive Systems for the Large Civil TiltRotor (LCTR2) Rotorcraft

In a series of study tasks conducted as a part of NASA's Fundamental Aeronautics Program, Rotary Wing Project, Boeing and Rolls-Royce explored propulsion, drive, and rotor system options for the NASA Large Civil Tilt Rotor (LCTR2) concept vehicle. The original objective of this study was to identify engine and drive system configurations to reduce rotor tip speed during cruise conditions and quantify the associated benefits. Previous NASA studies concluded that reducing rotor speed (from 650 fps hover tip speed) during cruise would reduce vehicle gross weight and fuel burn. Initially, rotor cruise speed ratios of 54% of the hover tip speed were of most interest during operation at cruise air speed of 310 ktas. Interim results were previously reported1 for cruise tip speed ratios of 100%, 77%, and 54% of the hover tip speed using engine and/or gearbox features to achieve the reduction. Technology levels from commercial off-the-shelf (COTS), through entry-in-service (EIS) dates of 2025 and 2035 were considered to assess the benefits of advanced technology on vehicle gross weight and fuel burn. This technical paper presents the final study results in terms of vehicle sizing and fuel burn as well as Operational and Support (O&S) costs. New vehicle sizing at rotor tip speed reduced to 65% of hover is presented for engine performance with an EIS 2035 fixed geometry variable speed power turbine. LCTR2 is also evaluated for missions range cases of 400, 600, 800, 1000, and 1200 nautical miles and cruise air speeds of 310, 350 and 375 ktas.

Robuck, Mark↗

Entry Systems and Vehicle Development Branch (Code TSS)

- TSS was established in 2009 to work with discipline-oriented branches (TSA, TSM, TSF) and provide a leadership approach for sub-system design and hardware components that comprise entry systems. - Currently, branch comprises 11 civil servants and 11 contractors. - 19 NASA Honor Awards in Exceptional Service (2), Achievement (2), Engineering Achievement (5), Early Career Achievement (5), and Outstanding Leadership (5). - In the last decade, TSS has built up core competencies that enable the branch to deliver end-to-end entry systems and vehicle development capabilities.

Antonella Alunni↗

High-speed civil transport study. Summary

A system of study of the potential for a high speed commercial transport aircraft addressed technology, economic, and environmental constraints. Market projections indicated a need for fleets of transport with supersonic or greater cruise speeds by the years 2000 to 2005. The associated design requirements called for a vehicle to carry 250 to 300 passengers over a range of 5000 to 6000 nautical miles. The study was initially unconstrained in terms of vehicle characteristics, such as cruise speed, propulsion systems, fuels, or structural materials. Analyses led to a focus on the most promising vehicle concepts. These were concepts that used a kerosene type fuel and cruised at Mach numbers between 2.0 to 3.2. Further systems study identified the impact of environmental constraints (for community noise, sonic boom, and engine emissions) on economic attractiveness and technological needs. Results showed that current technology cannot produce a viable high speed civil transport. Significant advances are needed to take off gross weight and allow for both economic attractiveness and environment acceptability. Specific technological requirements were identified to meet these needs.

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Test results of a Stirling engine utilizing heat exchanger modules with an integral heat pipe

The Heat Pipe Stirling Engine (HP-1000), a free-piston Stirling engine incorporating three heat exchanger modules, each having a sodium filled heat pipe, has been tested at the NASA-Lewis Research Center as part of the Civil Space Technology Initiative (CSTI). The heat exchanger modules were designed to reduce the number of potential flow leak paths in the heat exchanger assembly and incorporate a heat pipe as the link between the heat source and the engine. An existing RE-1000 free-piston Stirling engine was modified to operate using the heat exchanger modules. This paper describes heat exchanger module and engine performance during baseline testing. Condenser temperature profiles, brake power, and efficiency are presented and discussed.

Skupinski, Robert C.↗

Inlet-Compressor Analysis Performed Using Coupled Computational Fluid Dynamics Codes

A thorough understanding of dynamic interactions between inlets and compressors is extremely important to the design and development of propulsion control systems, particularly for supersonic aircraft such as the High-Speed Civil Transport (HSCT). Computational fluid dynamics (CFD) codes are routinely used to analyze individual propulsion components. By coupling the appropriate CFD component codes, it is possible to investigate inlet-compressor interactions. The objectives of this work were to gain a better understanding of inlet-compressor interaction physics, formulate a more realistic compressor-face boundary condition for time-accurate CFD simulations of inlets, and to take a first step toward the CFD simulation of an entire engine by coupling multidimensional component codes. This work was conducted at the NASA Lewis Research Center by a team of civil servants and support service contractors as part of the High Performance Computing and Communications Program (HPCCP).

Cole, Gary L.↗

Review of Aeronautical Wind Tunnel Facilities

The nation's aeronautical wind tunnel facilities constitute a valuable technological resource and make a significant contribution to the global supremacy of U.S. aircraft, both civil and military. At the request of NASA, the National Research Council's Aeronautics and Space Engineering Board organized a commitee to review the state of repair, adequacy, and future needs of major aeronautical wind tunnel facilities in meeting national goals. The comittee identified three main areas where actions are needed to sustain the capability of NASA's aeronautical wind tunnel facilities to support the national aeronautical research and development activities: tunnel maintenance and upgrading, productivity enhancement, and accommodation of new requirements (particularly in hypersonics). Each of these areas are addressed and the committee recommendations for appropriate actions presented.

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A grid generation system for multi-disciplinary design optimization

A general multi-block three-dimensional volume grid generator is presented which is suitable for Multi-Disciplinary Design Optimization. The code is timely, robust, highly automated, and written in ANSI 'C' for platform independence. Algebraic techniques are used to generate and/or modify block face and volume grids to reflect geometric changes resulting from design optimization. Volume grids are generated/modified in a batch environment and controlled via an ASCII user input deck. This allows the code to be incorporated directly into the design loop. Generated volume grids are presented for a High Speed Civil Transport (HSCT) Wing/Body geometry as well a complex HSCT configuration including horizontal and vertical tails, engine nacelles and pylons, and canard surfaces.

Jones, William T.↗

Future Aerospace Technology in the Service of the Alliance: Sustained Hypersonic Flight - Volume 3

Sustained Hypersonic Flight capability is envisioned for several future military and civilian applications, such as long range immediate reaction reconnaissance, high speed interception of air targets, long range precision strike against hardened or time critical targets, and access to space. The inherent reduction in time-to-target and low vulnerability will permit new operational tactics. The symposium outlined mission needs and operational scenarios for hypersonic vehicles. Addressed were: Technological issues and challenges in external hypersonic aerodynamics and design, propulsion and engine/airframe integration, military ramjet applications, overall system design including structures and materials development needs, and test facilities. Ground based test facilities cannot provide full simulation at Mach numbers above 5. Therefore, the use of Computational Fluid Dynamics design tools is essential. For routine use of the computational tools in analysis, design and optimization, it is necessary to reduce the time for the entire computational process by two orders of magnitude. Hypersonic boundary layer transition remains a critical design issue because of the important impact on engine drag and on heating, which can affect the choice of materials and thermal protection systems. In addition, reliable prediction of scramjet net thrust is an absolute must in resolving hypersonic air breathing vehicle design issues. Due to current facility and computational shortfalls, the development of future hypersonic flight systems requires research flight tests in the technology areas of boundary layer transition and air-breathing propulsion engine performance. For sustained hypersonic flight beyond Mach 6, the supersonic combustion ramjet (scramjet) engine is the only choice for the near future. Only this air-breathing concept offers a significant promise of large reductions in required propellant fractions, increased payload fractions, and reduced size vehicles, together with a foreseeable technological feasibility. Airframe/engine integration, combustor design and thermal management are the predominant engineering tasks. Fuels, hydrogen or hydrocarbon, must be matched to the operational needs of military or civil use. Experience in existing ramjet propelled missiles capable of speeds up to Mach 4 can support the development effort. The potential mission and cost benefits of sustained hypersonic flight to both military and civil applications are tremendous. From the budget point of view, the possibility of sharing development costs between military and civil programs offers a specific advantage.

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A Grid Generation System for Multi-Disciplinary Design Optimization

A general multi-block three-dimensional volume grid generator is presented which is suitable for Multi-Disciplinary Design Optimization. The code is fast, robust, highly automated, and written in ANSI C for platform independence. Algebraic techniques are used to generate and/or modify block face and volume grids to reflect geometric changes resulting from design optimization. Volume grids are generated/modified in a batch environment and controlled via an ASCII user input deck. This allows the code to be incorporated directly into the design loop. Generated volume grids are presented for a High Speed Civil Transport (HSCT) Wing/Body geometry as well a complex HSCT configuration including horizontal and vertical tails, engine nacelles and pylons, and canard surfaces.

Jones, William T.↗

Effect of Cyclic Thermal Loads on Fatigue Reliability in Polymer Matrix Composites

Technological solutions that will ensure the economic viability and environmental compatibility of a future High Speed Civil Transport plane are currently being sought. Lighter structural materials for both airframe primary structures and engine structure components are being investigated. We believe that such objectives can be achieved through the use of high-temperature composites as well as other conventional, lighter weight alloys. One of the prime issues for these structural components is assured long-term behavior with a specified reliability. An investigation was conducted to describe a computational simulation methodology for predicting fatigue life, reliability, and probabilistic long-term behavior of polymer matrix composites. A unified time-, stress-, and load-dependent Multi- Factor Interaction Equation (MFIE) model developed at the NASA Lewis Research Center was used to simulate the long-term behavior of polymer matrix composites.

Chamis, Christos C.↗