Integrated control and health management. Orbit transfer rocket engine technology program

To insure controllability of the baseline design for a 7500 pound thrust, 10:1 throttleable, dual expanded cycle, Hydrogen-Oxygen, orbit transfer rocket engine, an Integrated Controls and Health Monitoring concept was developed. This included: (1) Dynamic engine simulations using a TUTSIM derived computer code; (2) analysis of various control methods; (3) Failure Modes Analysis to identify critical sensors; (4) Survey of applicable sensors technology; and, (5) Study of Health Monitoring philosophies. The engine design was found to be controllable over the full throttling range by using 13 valves, including an oxygen turbine bypass valve to control mixture ratio, and a hydrogen turbine bypass valve, used in conjunction with the oxygen bypass to control thrust. Classic feedback control methods are proposed along with specific requirements for valves, sensors, and the controller. Expanding on the control system, a Health Monitoring system is proposed including suggested computing methods and the following recommended sensors: (1) Fiber optic and silicon bearing deflectometers; (2) Capacitive shaft displacement sensors; and (3) Hot spot thermocouple arrays. Further work is needed to refine and verify the dynamic simulations and control algorithms, to advance sensor capabilities, and to develop the Health Monitoring computational methods

Index to 1983 NASA Tech Briefs, volume 8, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1983 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Orbit Transfer Rocket Engine Technology Program: Advanced engine study, task D.1/D.3

Concepts for space maintainability of OTV engines were examined. An engine design was developed which was driven by space maintenance requirements and by a failure mode and effects (FME) analysis. Modularity within the engine was shown to offer cost benefits and improved space maintenance capabilities. Space operable disconnects were conceptualized for both engine change-out and for module replacement. Through FME mitigation the modules were conceptualized to contain the least reliable and most often replaced engine components. A preliminary space maintenance plan was developed around a controls and condition monitoring system using advanced sensors, controls, and condition monitoring concepts. A complete engine layout was prepared satisfying current vehicle requirements and utilizing projected component advanced technologies. A technology plan for developing the required technology was assembled

Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Aeronautical engineering: A continuing bibliography with indexes (supplement 239)

This bibliography lists 454 reports, articles, and other documents introduced into the NASA scientific and technical information system in April, 1989. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

The 1992 Research/Technology report

The 1992 Research & Technology report is organized so that a broad cross section of the community can readily use it. A short introductory paragraph begins each article and will prove to be an invaluable reference tool for the layperson. The approximately 200 articles summarize the progress made during the year in various technical areas and portray the technical and administrative support associated with Lewis technology programs

Index to NASA Tech Briefs, 1975

This index contains abstracts and four indexes--subject, personal author, originating Center, and Tech Brief number--for 1975 Tech Briefs

Impact of electrically assisted turbocharging on the transient response of an off-highway diesel engine

Engine boosting via turbocharging is a method to increase the engine power output with minimal or no increase in engine parasitic, frictional and pumping losses. Turbocharging in conjunction with engine down-sizing and down-speeding allows a reduction of engine fuel consumption, while maintaining a high engine power output. However, turbocharging introduces a lag in engine transient response, caused by the finite amount of time required by the turbocharger to accelerate, which has to be minimized. Electric turbocharger assistance consists of coupling an electric motor/generator to a standard turbocharger. The scope of the motor/generator is to increase the power available to accelerate the rotor assembly, so that the time to boost is reduced. The motor/generator could also be utilized to brake the turbocharger to control boost and avoid over-speeds, thus replacing the conventional waste-gate. Furthermore, electric assistance allows turbocompounding to be implemented. Turbocompounding improves the engine efficiency by utilizing the turbine and motor/generator to recuperate additional exhaust flow energy. In this thesis, the electric turbocharger assistance impact on the turbocharger and engine performance is studied. An electrically assisted turbocharger prototype has been developed by industrial partners and it has been tested by the author of this thesis. The performance of the turbocharger turbine and motor/generator has been characterized over the full speed range and the impact of the electric assistance on the turbine flow has been investigated experimentally. It has not been possible to characterize the turbine up to choking conditions, so the data has been extrapolated via a mean-line model. The performance data obtained has been utilized to generate a model of the assisted turbocharger, which has been coupled to a one-dimensional model of a non-highway 7-litre diesel engine. This model has been utilized to study the impact of electric turbocharger assistance on the engine transient performance. The electrical machine characterization revealed that the switched reluctance motor/generator operates efficiently up to a speed of 135,000 rev/min, making it one of the fastest running switched reluctance machines of this size. The peak machine efficiency is 93% (excluding the turbocharger bearing losses) and the maximum power output measured is 5.3 kW in generating mode and 4.3 kW in motoring mode. The motor/generator rotor aerodynamic drag loss has been calculated via computational fluid dynamics software and has been found to be 63 W at 140,000 rev/min. Via a novel experimental technique, it has been possible to characterize the turbocharger turbine down to an expansion ratio of 1.00. This experiment revealed that the mass flow rate drops to zero at an expansion ratio higher than unity and that below this critical pressure ratio the turbine flow is reversed. The characterization of the turbine during speed transients showed that the operating point on the performance map deviates from the quasi-steady line. This indicates that minor unsteady effects occur in the turbine and exhaust manifold flow. A further experiment revealed that the motor/generator torque oscillations have a negligible impact on the turbine performance. The engine simulations showed that the ideal electric assistance motoring power for this application is in the 5 to 10 kW range. A 5 kW machine reduces the engine speed drop, which occurs when the engine load is suddenly increased, by up to 83%, depending on the initial load and load step size, and reduces the time to recover the original speed by up to 86%. The simulations also revealed that electric assistance is more effective than the turbine variable geometry system in improving the engine transient response, but the variable geometry system is useful to optimize boost for engine specific fuel consumption over different engine loading conditions.Open Acces

Aeronautical engineering: A continuing bibliography with indexes (supplement 242)

This bibliography lists 466 reports, articles, and other documents introduced into the NASA scientific and technical information system in July, 1989. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences