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At least 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Free-piston Stirling engine conceptual design and technologies for space power, phase 1

As part of the SP-100 program, a phase 1 effort to design a free-piston Stirling engine (FPSE) for a space dynamic power conversion system was completed. SP-100 is a combined DOD/DOE/NASA program to develop nuclear power for space. This work was completed in the initial phases of the SP-100 program prior to the power conversion concept selection for the Ground Engineering System (GES). Stirling engine technology development as a growth option for SP-100 is continuing after this phase 1 effort. Following a review of various engine concepts, a single-cylinder engine with a linear alternator was selected for the remainder of the study. The relationships of specific mass and efficiency versus temperature ratio were determined for a power output of 25 kWe. This parametric study was done for a temperature ratio range of 1.5 to 2.0 and for hot-end temperatures of 875 K and 1075 K. A conceptual design of a 1080 K FPSE with a linear alternator producing 25 kWe output was completed. This was a single-cylinder engine designed for a 62,000 hour life and a temperature ratio of 2.0. The heat transport systems were pumped liquid-metal loops on both the hot and cold ends. These specifications were selected to match the SP-100 power system designs that were being evaluated at that time. The hot end of the engine used both refractory and superalloy materials; the hot-end pressure vessel featured an insulated design that allowed use of the superalloy material. The design was supported by the hardware demonstration of two of the component concepts - the hydrodynamic gas bearing for the displacer and the dynamic balance system. The hydrodynamic gas bearing was demonstrated on a test rig. The dynamic balance system was tested on the 1 kW RE-1000 engine at NASA Lewis.

Penswick, L. Barry↗
NASA NTRS1992

Engine monitoring display study

The current study is part of a larger NASA effort to develop displays for an engine-monitoring system to enable the crew to monitor engine parameter trends more effectively. The objective was to evaluate the operational utility of adding three types of information to the basic Boeing Engine Indicating and Crew Alerting System (EICAS) display formats: alphanumeric alerting messages for engine parameters whose values exceed caution or warning limits; alphanumeric messages to monitor engine parameters that deviate from expected values; and a graphic depiction of the range of expected values for current conditions. Ten training and line pilots each flew 15 simulated flight scenarios with five variants of the basic EICAS format; these variants included different combinations of the added information. The pilots detected engine problems more quickly when engine alerting messages were included in the display; adding a graphic depiction of the range of expected values did not affect detection speed. The pilots rated both types of alphanumeric messages (alert and monitor parameter) as more useful and easier to interpret than the graphic depiction. Integrating engine parameter messages into the EICAS alerting system appears to be both useful and preferred.

Hornsby, Mary E.↗
NASA NTRS1991

Space civil engineering - A new discipline

Space Civil Engineering is an emerging engineering discipline that focuses on extending and expanding the Civil Engineering know-how and practice to the development and maintenance of infrastructure on celestial bodies. Space Civil Engineering is presently being developed as a new discipline within the Department of Civil Engineering at Colorado State University under a recently established NASA Space Grant College Program. Academic programs geared toward creating Space Civil Engineering Options at both undergraduate and graduate levels are being formulated. Basic ideas and concepts of the curriculum in the Space Civil Engineering Option at both undergraduate and graduate levels are presented. The role of Space Civil Engineering in the Space Program is discussed.

Sadeh, Willy Z.↗
NASA NTRS1992

Space Shuttle Orbiter Fleet Leader Orbital Maneuvering Engine SN 002A injector replacement

During testing of the Fleet Leader Orbital Maneuvering Engine (OME) Serial Number (SN) 002A at the White Sands Test Facility (WSTF) in 1983 the injector was inadvertently damaged. After testing was completed in 1985, there was a concern that the performance of the engine and its response to specific test conditions might not be sufficiently representative of flight engines to provide valid test results. To correct this damage, the engine was returned to the manufacturer to replace the injector. The task assigned was to evaluate the damage and generate a unique process to repair the Fleet Leader OME while providing minimum impact to the overall life condition of the engine. In addition to successfully performing the repair operation, the as received condition of the engine and its components were documented for Fleet Leader reference. The engine is currently at WSTF where it has accumulated 11,341 seconds of firing time to date, 2615 seconds of which have occurred since the engine repair.

Riccio, Joseph R.↗
NASA NTRS1992

NASA systems engineering handbook. Draft

This handbook is intended to provide information on systems engineering that will be useful to NASA system engineers, especially new ones. Its primary objective is to provide a generic description of systems engineering as it should be applied throughout NASA. Field Center Handbooks are encouraged to provide center-specific details of implementation. For NASA system engineers to choose to keep a copy of this handbook at their elbows, it must provide answers that cannot be easily found elsewhere. Consequently, it provides NASA-relevant perspectives and NASA-particular data. NASA management instructions (NMI's) are referenced when applicable. This handbook's secondary objective is to serve as a useful companion to all of the various courses in systems engineering that are being offered under NASA's auspices. The coverage of systems engineering is general to techniques, concepts, and generic descriptions of processes, tools, and techniques. It provides good systems engineering practices, and pitfalls to avoid. This handbook describes systems engineering as it should be applied to the development of major NASA product and producing systems.

Shishko, Robert↗
NASA NTRS1993

Dual Engine application of the Performance Seeking Control algorithm

The Dual Engine Performance Seeking Control (PSC) flight/propulsion optimization program has been developed and will be flown during the second quarter of 1993. Previously, only single engine optimization was possible due to the limited capability of the on-board computer. The implementation of Dual Engine PSC has been made possible with the addition of a new state-of-the-art, higher throughput computer. As a result, the single engine PSC performance improvements already flown will be demonstrated on both engines, simultaneously. Dual Engine PSC will make it possible to directly compare aircraft performance with and without the improvements generated by PSC. With the additional thrust achieved with PSC, significant improvements in acceleration times and time to climb will be possible. PSC is also able to reduce deceleration time from supersonic speeds. This paper traces the history of the PSC program, describes the basic components of PSC, discusses the development and implementation of Dual Engine PSC including additions to the code, and presents predictions of the impact of Dual Engine PSC on aircraft performance.

Mueller, F. D.↗
NASA NTRS1993

Nonlinear dynamic simulation of single- and multi-spool core engines

In this paper a new computational method for accurate simulation of the nonlinear dynamic behavior of single- and multi-spool core engines, turbofan engines, and power generation gas turbine engines is presented. In order to perform the simulation, a modularly structured computer code has been developed which includes individual mathematical modules representing various engine components. The generic structure of the code enables the dynamic simulation of arbitrary engine configurations ranging from single-spool thrust generation to multi-spool thrust/power generation engines under adverse dynamic operating conditions. For precise simulation of turbine and compressor components, row-by-row calculation procedures were implemented that account for the specific turbine and compressor cascade and blade geometry and characteristics. The dynamic behavior of the subject engine is calculated by solving a number of systems of partial differential equations, which describe the unsteady behavior of the individual components. In order to ensure the capability, accuracy, robustness, and reliability of the code, comprehensive critical performance assessment and validation tests were performed. As representatives, three different transient cases with single- and multi-spool thrust and power generation engines were simulated. The transient cases range from operating with a prescribed fuel schedule, to extreme load changes, to generator and turbine shut down.

Schobeiri, T.↗
NASA NTRS1993

Three-dimensional modeling of diesel engine intake flow, combustion and emissions-2

A three-dimensional computer code, KIVA, is being modified to include state-of-the-art submodels for diesel engine flow and combustion. Improved and/or new submodels which have already been implemented and previously reported are: wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo'vich NO(x), and spray/wall impingement with rebounding and sliding drops. Progress on the implementation of improved spray drop drag and drop breakup models, the formulation and testing of a multistep kinetics ignition model, and preliminary soot modeling results are described. In addition, the use of a block structured version of KIVA to model the intake flow process is described. A grid generation scheme was developed for modeling realistic (complex) engine geometries, and computations were made of intake flow in the ports and combustion chamber of a two-intake-value engine. The research also involves the use of the code to assess the effects of subprocesses on diesel engine performance. The accuracy of the predictions is being tested by comparisons with engine experiments. To date, comparisons were made with measured engine cylinder pressure, temperature and heat flux data, and the model results are in good agreement with the experiments. Work is in progress that will allow validation of in-cylinder flow and soot formation predictions. An engine test facility is described that is being used to provide the needed validation data. Test results were obtained showing the effect of injection rate and split injections on engine performance and emissions.

Reitz, R. D.↗
NASA NTRS1993

NASA Propulsion Engineering Research Center, volume 1

Over the past year, the Propulsion Engineering Research Center at The Pennsylvania State University continued its progress toward meeting the goals of NASA's University Space Engineering Research Centers (USERC) program. The USERC program was initiated in 1988 by the Office of Aeronautics and Space Technology to provide an invigorating force to drive technology advancements in the U.S. space industry. The Propulsion Center's role in this effort is to provide a fundamental basis from which the technology advances in propulsion can be derived. To fulfill this role, an integrated program was developed that focuses research efforts on key technical areas, provides students with a broad education in traditional propulsion-related science and engineering disciplines, and provides minority and other under-represented students with opportunities to take their first step toward professional careers in propulsion engineering. The program is made efficient by incorporating government propulsion laboratories and the U.S. propulsion industry into the program through extensive interactions and research involvement. The Center is comprised of faculty, professional staff, and graduate and undergraduate students working on a broad spectrum of research issues related to propulsion. The Center's research focus encompasses both current and advanced propulsion concepts for space transportation, with a research emphasis on liquid propellant rocket engines. The liquid rocket engine research includes programs in combustion and turbomachinery. Other space transportation modes that are being addressed include anti-matter, electric, nuclear, and solid propellant propulsion. Outside funding supports a significant fraction of Center research, with the major portion of the basic USERC grant being used for graduate student support and recruitment. The remainder of the USERC funds are used to support programs to increase minority student enrollment in engineering, to maintain Center infrastructure, and to develop research capability in key new areas. Significant research programs in propulsion systems for air and land transportation complement the space propulsion focus. The primary mission of the Center is student education. The student program emphasizes formal class work and research in classical engineering and science disciplines with applications to propulsion.

Source record↗
NASA NTRS1993

Orbit transfer rocket engine technology program

An advanced near term (1990's) space-based Orbit Transfer Vehicle Engine (OTVE) system was designed, and the technologies applicable to its construction, maintenance, and operations were developed under Tasks A through F of the Orbit Transfer Rocket Engine Technology Program. Task A was a reporting task. In Task B, promising OTV turbomachinery technologies were explored: two stage partial admission turbines, high velocity ratio diffusing crossovers, soft wear ring seals, advanced bearing concepts, and a rotordynamic analysis. In Task C, a ribbed combustor design was developed. Possible rib and channel geometries were chosen analytically. Rib candidates were hot air tested and laser velocimeter boundary layer analyses were conducted. A channel geometry was also chosen on the basis of laser velocimeter data. To verify the predicted heat enhancement effects, a ribbed calorimeter spool was hot fire tested. Under Task D, the optimum expander cycle engine thrust, performance and envelope were established for a set of OTV missions. Optimal nozzle contours and quick disconnects for modularity were developed. Failure Modes and Effects Analyses, maintenance and reliability studies and component study results were incorporated into the engine system. Parametric trades on engine thrust, mixture ratio, and area ratio were also generated. A control system and the health monitoring and maintenance operations necessary for a space-based engine were outlined in Task E. In addition, combustor wall thickness measuring devices and a fiberoptic shaft monitor were developed. These monitoring devices were incorporated into preflight engine readiness checkout procedures. In Task F, the Integrated Component Evaluator (I.C.E.) was used to demonstrate performance and operational characteristics of an advanced expander cycle engine system and its component technologies. Sub-system checkouts and a system blowdown were performed. Short transitions were then made into main combustor ignition and main stage operation.

Gustafson, N. B.↗
NASA NTRS1992

Engine system assessment study using Martian propellants

A top-level feasibility study was conducted that identified and characterized promising chemical propulsion system designs which use two or more of the following propellant combinations: LOX/H2, LOX/CH4, and LOX/CO. The engine systems examined emphasized the usage of common subsystem/component hardware where possible. In support of this study, numerous mission scenarios were characterized that used various combinations of Earth, lunar, and Mars propellants to establish engine system requirements to assess the promising engine system design concept examined, and to determine overall exploration leverage of such systems compared to state-of-the-art cryogenic (LOX/H2) propulsion systems. Initially in the study, critical propulsion system technologies were assessed. Candidate expander and gas generator cycle LOX/H2/CO, LOX/H2/CH4, and LOX/CO/CH4 engine system designs were parametrically evaluated. From this evaluation baseline, tripropellant Mars Transfer Vehicle (MTV) LOX cooled and bipropellant Lunar Excursion Vehicle (LEV) and Mars Excursion Vehicle (MEV) engine systems were identified. Representative tankage designs for a MTV were also investigated. Re-evaluation of the missions using the baseline engine design showed that in general the slightly lower performance, smaller, lower weight gas generator cycle-based engines required less overall mission Mars and in situ propellant production (ISPP) infrastructure support compared to the larger, heavier, higher performing expander cycle engine systems.

Pelaccio, Dennis↗
NASA NTRS1989

Stratified charge rotary engine combustion studies

Analytical and experimental studies of the combustion process in a stratified charge rotary engine (SCRE) continue to be the subject of active research in recent years. Specifically to meet the demand for more sophisticated products, a detailed understanding of the engine system of interest is warranted. With this in mind the objective of this work is to develop an understanding of the controlling factors that affect the SCRE combustion process so that an efficient power dense rotary engine can be designed. The influence of the induction-exhaust systems and the rotor geometry are believed to have a significant effect on combustion chamber flow characteristics. In this report, emphasis is centered on Laser Doppler Velocimetry (LDV) measurements and on qualitative flow visualizations in the combustion chamber of the motored rotary engine assembly. This will provide a basic understanding of the flow process in the RCE and serve as a data base for verification of numerical simulations. Understanding fuel injection provisions is also important to the successful operation of the stratified charge rotary engine. Toward this end, flow visualizations depicting the development of high speed, high pressure fuel jets are described. Friction is an important consideration in an engine from the standpoint of lost work, durability and reliability. MSU Engine Research Laboratory efforts in accessing the frictional losses associated with the rotary engine are described. This includes work which describes losses in bearing, seal and auxillary components. Finally, a computer controlled mapping system under development is described. This system can be used to map shapes such as combustion chamber, intake manifolds or turbine blades accurately.

Shock, H.↗
NASA NTRS1995

Wave rotor-enhanced gas turbine engines

The benefits of wave rotor-topping in small (400 to 600 hp-class) and intermediate (3000 to 4000 hp-class) turboshaft engines, and large (80,000 to 100,000 lb(sub f)-class) high bypass ratio turbofan engines are evaluated. Wave rotor performance levels are calculated using a one-dimensional design/analysis code. Baseline and wave rotor-enhanced engine performance levels are obtained from a cycle deck in which the wave rotor is represented as a burner with pressure gain. Wave rotor-toppings is shown to significantly enhance the specific fuel consumption and specific power of small and intermediate size turboshaft engines. The specific fuel consumption of the wave rotor-enhanced large turbofan engine can be reduced while operating at significantly reduced turbine inlet temperature. The wave rotor-enhanced engine is shown to behave off-design like a conventional engine. Discussion concerning the impact of the wave rotor/gas turbine engine integration identifies tenable technical challenges.

Welch, Gerard E.↗
NASA NTRS1995

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 51: Workplace communications skills and the value of communications and information-use skills instruction: Engineering students' perspectives

Studies indicate that communications and information-related activities take up a substantial portion of an engineer's work week; therefore, effective communications and information use skills are one of the key engineering competencies that recent graduates of engineering programs are expected to possess. Feedback from industry rates communications and information use skills of entry-level engineers low. Missing from current discussions of communications and information use skills and competencies for engineering students is a clear explanation from the professional engineering community about what constitutes 'acceptable and desirable communications and information norms' within that community. To gather adequate and generalizable data about communications and information skills instruction and to provide a student perspective on the communications skills of engineers, we undertook a national study of aerospace engineering students in March 1993. The study included questions about the importance of certain communications and information skills to professional success, the instruction students had received in these skills, and perceived helpfulness of the instruction. Selected results from the study study are reported in this paper.

Pinelli, Thomas E.↗
NASA NTRS1995

NASA Systems Engineering Handbook

This handbook brings the fundamental concepts and techniques of systems engineering to NASA personnel in a way that recognizes the nature of NASA systems and environment. It is intended to accompany formal NASA training courses on systems engineering and project management when appropriate, and is designed to be a top-level overview. The concepts were drawn from NASA field center handbooks, NMI's/NHB's, the work of the NASA-wide Systems Engineering Working Group and the Systems Engineering Process Improvement Task team, several non-NASA textbooks and guides, and material from independent systems engineering courses taught to NASA personnel. Five core chapters cover systems engineering fundamentals, the NASA Project Cycle, management issues in systems engineering, systems analysis and modeling, and specialty engineering integration. It is not intended as a directive. Superseded by: NASA/SP-2007-6105 Rev 1 (20080008301).

Shishko, Robert↗
NASA NTRS1998

Teaching Engineering Students Team Work

The purpose of this manual is to provide professor's in engineering classes which the background necessary to use student team projects effectively. This manual describes some of the characteristics of student teams and how to use them in class. It provides a set of class activities and films which can be used to introduce and support student teams. Finally, a set of teaching modules used in freshmen, sophomore, and senior aeronautical engineering classes are presented. This manual was developed as part of a NASA sponsored project to improve the undergraduate education of aeronautical engineers. The project has helped to purchase a set of team work films which can be checked out from Cal Poly's Learning Resources Center in the Kennedy Library. Research for this project has included literature reviews on team work and cooperative learning; interviews, observations, and surveys of Cal Poly students from Industrial and Manufacturing Engineering, Aeronautical Engineering and Psychology; participation in the Aeronautical Engineering senior design lab; and interviews with engineering faculty. In addition to this faculty manual, there is a student team work manual which has been designed to help engineering students work better in teams.

Levi, Daniel↗
NASA NTRS2001

Simulation of MC-1 Engine on Real-Time Station

The MC-1 rocket engine is a new, 60,000-pound-thrust engine designed to boost small spacecraft carrying payloads weighing up to 500 pounds. The engine was designed in-house at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, and built by SUMMA Technology, Inc. A vital part of the success of the engine development was the verification of the Propulsion System Controller (PSC) used to control the MC-1 engine during development testing at test facilities in Mississippi and California. The MC-1 engine simulation software was developed on the Applied Dynamics, Inc.'s Real-Time Station (RTS) computer system (ESL) to verify the PSC's hardware and software performance in the Marshall Avionics System Testbed's (MAST) Engine Simulation Lab at the MSFC. The engine model includes the simulation of pressure transducers, thermocouple sensors and valve-positions.

Ly, William↗
NASA NTRS2001

A Roadmap for Aircraft Engine Life Extending Control

The concept of Aircraft Engine Life Extending Control is introduced. A brief description of the tradeoffs between performance and engine life are first explained. The overall goal of the life extending controller is to reduce the engine operating cost by extending the on-wing engine life while improving operational safety. The research results for NASA's Rocket Engine life extending control program are also briefly described. Major building blocks of the Engine Life Extending Control architecture are examined. These blocks include: life prediction models, engine operation models, stress and thermal analysis tools, control schemes, and intelligent control systems. The technology areas that would likely impact the successful implementation of an aircraft engine life extending control are also briefly described. Near, intermediate, and long term goals of NASA's activities are also presented.

Guo, Ten-Huei↗