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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
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Computer program for a four-cylinder-Stirling-engine controls simulation

A four cylinder Stirling engine, transient engine simulation computer program is presented. The program is intended for controls analysis. The associated engine model was simplified to shorten computer calculation time. The model includes engine mechanical drive dynamics and vehicle load effects. The computer program also includes subroutines that allow: (1) acceleration of the engine by addition of hydrogen to the system, and (2) braking of the engine by short circuiting of the working spaces. Subroutines to calculate degraded engine performance (e.g., due to piston ring and piston rod leakage) are provided. Input data required to run the program are described and flow charts are provided. The program is modular to allow easy modification of individual routines. Examples of steady state and transient results are presented.

Daniels, C. J.↗
NASA NTRS1986

Four-Cylinder Stirling Engine Control Simulation

Four-cylinder, Stirling-engine, transient-engine-simulation computer program developed. Program intended for control analysis. Associated engine model simplified to shorten computer calculation time. Model includes engine mechanical-drive dynamics and vehicle-load effects. Computer program also includes subroutines that allow acceleration of engine by addition of hydrogen to system and braking of engine by short circuiting of working spaces.

Daniele, C. J.↗
NASA NTRS1992

Overview of magnetic suspension research at Langley Research Center

An overview of research in small- and large-gap magnetic suspension systems at LaRC is presented. The overview is limited to systems which have been built as laboratory models or engineering models. Small-gap systems applications include the Annular Momentum Control Device (AMCD), which is a momentum storage device for the stabilization and control of spacecraft, and the Annular Suspension and Pointing System (ASPS), which is a general purpose pointing mount designed to provide orientation, mechanical isolation, and fine pointing space experiments. These devices are described and control and linearization approaches for the magnetic suspension systems for these devices are discussed. Large-gap systems applications at LaRC have been almost exclusively wind tunnel magnetic suspension systems. A brief description of these efforts is also presented.

Groom, Nelson J.↗
NASA NTRS1993

Measuring Fluctuating Pressures With Recessed Gauges

Report discusses use of pressure gauges mounted in recesses in interior wall of model scramjet engine. Consists of brief memorandum plus excerpts from NASA Technical Paper 3189, "Unsteady Pressure Loads In A Generic High-Speed Engine Model." Focuses mainly on factors affecting accuracy of gauge readings.

Parrott, Tony L.↗
NASA NTRS1992

Performances of the Imaging Proportional Counter of the Stellar X-ray Polarimeter

The Stellar X-ray Polarimeter (SXRP) will be mounted on the focal plane of one of the two SODART telescopes aboard the Russian mission Spectrum-X-gamma. The SXRP employs the same Imaging Proportional Counters for both the Bragg and the scattering stages. An account is presently given of the main characteristics of these detectors and their performance, on the basis of tests at the technical-model and engineering model levels of development.

Costa, E.↗
NASA NTRS1995

Research project for increasing pool of minority engineers

The Tennessee State University (TSU) Research Project for Increasing the Pool of Minority Engineers is designed to develop engineers who have academic and research experiences in technical areas of interest to NASA. These engineers will also have some degree of familiarity with NASA Lewis Research Center as a result of interaction with Lewis engineers, field trips and internships at Lewis. The Research Project has four components, which are: (1) Minority Introduction to Engineering (MITE), a high school precollege program, (2) engineering and technology previews, (3) the NASA LeRC Scholars program which includes scholarships and summer internships, and (4) undergraduate research experiences on NASA sponsored research. MITE is a two-week summer engineering camp designed to introduce minority high school students to engineering by exposing them to: (1) engineering role models (engineering students and NASA engineer), (2) field trips to engineering firms, (3) in addition to introducing youth to the language of the engineer (i.e., science, mathematics, technical writing, computers, and the engineering laboratory). Three MITE camps are held on the campus of TSU with an average of 40 participants. MITE has grown from 25 participants at its inception in 1990 to 118 participants in 1994 with participants from 17 states, including the District of Columbia, and 51 percent of the participants were female. Over the four-year period, 77 percent of the seniors who participated in MITE have gone to college, while 53 percent of those seniors in college are majoring in science, engineering or mathematics (SEM). This first Engineering and Technology Previews held in 1993 brought 23 youths from Cleveland, Ohio to TSU for a two-day preview of engineering and college life. Two previews are scheduled for 1994-1995. The NASA LeRC Scholars program provides scholarships and summer internships for minority engineering students majoring in electrical or mechanical engineering. Presently six (6) engineering students are in the Scholars program. The average GPA for the scholars is 3.239. Each scholar must maintain a minimum GPA of 3.000/4.000. NASA LeRC Fred Higgs has been awarded a GEM Fellowship. In addition, he will be presenting a paper entitled 'Design of Helical Spring Using Probabilistic Design Methodology' at the Middle Tennessee Section ASME Student Design Presentations in Nashville on March 23rd and at the National Conference on Undergraduate Research to be held at Union College, Schenectady, New York on April 20-22, 1995. Each of the scholars is working on one of the three NASA sponsored research projects in the college.

Rogers, Decatur B.↗
NASA NTRS1999

High Speed Civil Transport Aircraft Simulation: Reference-H Cycle 1, MATLAB Implementation

The mathematical model and associated code to simulate a high speed civil transport aircraft - the Boeing Reference H configuration - are described. The simulation was constructed in support of advanced control law research. In addition to providing time histories of the dynamic response, the code includes the capabilities for calculating trim solutions and for generating linear models. The simulation relies on the nonlinear, six-degree-of-freedom equations which govern the motion of a rigid aircraft in atmospheric flight. The 1962 Standard Atmosphere Tables are used along with a turbulence model to simulate the Earth atmosphere. The aircraft model has three parts - an aerodynamic model, an engine model, and a mass model. These models use the data from the Boeing Reference H cycle 1 simulation data base. Models for the actuator dynamics, landing gear, and flight control system are not included in this aircraft model. Dynamic responses generated by the nonlinear simulation are presented and compared with results generated from alternate simulations at Boeing Commercial Aircraft Company and NASA Langley Research Center. Also, dynamic responses generated using linear models are presented and compared with dynamic responses generated using the nonlinear simulation.

Sotack, Robert A.↗
NASA NTRS2003

Status of the NEXT Ion Engine Wear Test

The status of the NEXT 2000 hour wear test is presented. This test is being conducted with a 40 cm engineering model ion engine, designated EM1, at a beam current higher than listed on the NEXT throttle table. Pretest performance assessments demonstrated that EM1 satisfies all thruster performance requirements. As of 7/3/03, the ion engine has accumulated 406 hours of operation at a thruster input power of 6.9 kW. Overall ion engine performance, which includes thrust, thruster input power, specific impulse, and thrust efficiency, has been steady to date with no indications of performance degradation. Images of the downstream discharge cathode, neutralizer, and accelerator aperture surfaces have exhibited no significant erosion to date.

Soulas, George C.↗
NASA NTRS2004

Ion Engine Grid Gap Measurements

A simple technique for measuring the grid gap of an ion engine s ion optics during startup and steady-state operation was demonstrated with beam extraction. The grid gap at the center of the ion optics assembly was measured with a long distance microscope that was focused onto an alumina pin that protruded through the center accelerator grid aperture and was mechanically attached to the screen grid. This measurement technique was successfully applied to a 30 cm titanium ion optics assembly mounted onto an NSTAR engineering model ion engine. The grid gap and each grid s movement during startup from room temperature to both full and low power were measured. The grid gaps with and without beam extraction were found to be significantly different. The grid gaps at the ion optics center were both significantly smaller than the cold grid gap and different at the two power levels examined. To avoid issues associated with a small grid gap during thruster startup with titanium ion optics, a simple method was to operate the thruster initially without beam extraction to heat the ion optics. Another possible method is to apply high voltage to the grids prior to igniting the discharge because power deposition to the grids from the plasma is lower with beam extraction than without. Further testing would be required to confirm this approach.

Soulas, Gerge C.↗
NASA NTRS2004

NEXT Ion Engine 2000 Hour Wear Test Results

The results of the NEXT 2000 h wear test are presented. This test was conducted with a 40 cm engineering model ion engine, designated EM1, at a 3.52 A beam current and 1800 V beam power supply voltage. Performance tests, which were conducted over a throttling range of 1.1 to 6.9 kW throughout the wear test, demonstrated that EM1 satisfied all thruster performance requirements. The ion engine accumulated 2038 h of operation at a thruster input power of 6.9 kW, processing 43 kg of xenon. Overall ion engine performance, which includes thrust, thruster input power, specific impulse, and thrust efficiency, was steady with no indications of performance degradation. The ion engine was also inspected following the test. This paper presents these findings.

Soulas, George C.↗
NASA NTRS2006

Next-generation concurrent engineering: developing models to complement point designs

Concurrent Engineering Design (CED) teams have made routine the rapid development of point designs for space missions. The Jet Propulsion Laboratory's Team X is now evolving into a 'next-generation CED; in addition to a point design, the Team develops a model of the local trade space. The process is a balance between the power of a model developing tools and the creativity of humal experts, enabling the development of a variety of trade models for any space mission. This paper reviews the modeling method and its practical implementation in the ED environment. Example results illustrate the benefit of this approach.

concurrent engineering↗
NASA NTRS2011

DBD Plasma Actuators for Flow Control in Air Vehicles and Jet Engines - Simulation of Flight Conditions in Test Chambers by Density Matching

Dielectric Barrier Discharge (DBD) Plasma actuators for active flow control in aircraft and jet engines need to be tested in the laboratory to characterize their performance at flight operating conditions. DBD plasma actuators generate a wall-jet electronically by creating weakly ionized plasma, therefore their performance is affected by gas discharge properties, which, in turn, depend on the pressure and temperature at the actuator placement location. Characterization of actuators is initially performed in a laboratory chamber without external flow. The pressure and temperature at the actuator flight operation conditions need to be simultaneously set in the chamber. A simplified approach is desired. It is assumed that the plasma discharge depends only on the gas density, while other temperature effects are assumed to be negligible. Therefore, tests can be performed at room temperature with chamber pressure set to yield the same density as in operating flight conditions. The needed chamber pressures are shown for altitude flight of an air vehicle and for jet engines at sea-level takeoff and altitude cruise conditions. Atmospheric flight conditions are calculated from standard atmosphere with and without shock waves. The engine data was obtained from four generic engine models; 300-, 150-, and 50-passenger (PAX) aircraft engines, and a military jet-fighter engine. The static and total pressure, temperature, and density distributions along the engine were calculated for sea-level takeoff and for altitude cruise conditions. The corresponding chamber pressures needed to test the actuators were calculated. The results show that, to simulate engine component flows at in-flight conditions, plasma actuator should be tested over a wide range of pressures. For the four model engines the range is from 12.4 to 0.03 atm, depending on the placement of the actuator in the engine. For example, if a DBD plasma actuator is to be placed at the compressor exit of a 300 PAX engine, it has to be tested at 12.4 atm for takeoff, and 6 atm for cruise conditions. If it is to be placed at the low-pressure turbine, it has to be tested at 0.5 and 0.2 atm, respectively. These results have implications for the feasibility and design of DBD plasma actuators for jet engine flow control applications. In addition, the distributions of unit Reynolds number, Mach number, and velocity along the engine are provided. The engine models are non-proprietary and this information can be used for evaluation of other types of actuators and for other purposes.

Ashpis, David E.↗
NASA NTRSDate not supplied

The Advanced Geared Turbofan 30,000 lb f – electrified (AGTF30-e): A Virtual Testbed for Electrified Aircraft Propulsion Research

Electrified Aircraft Propulsion (EAP) is a growing topic of research with the potential to shape the future of commercial air travel. Here, detailed mathematical models serve an essential role in developing understanding and evaluating different technologies and design concepts. The Advanced Geared Turbofan 30,000 lb f – electrified (AGTF30-e) is an open-source software package developed by the National Aeronautics and Space Administration (NASA). The AGTF30-e provides a realistic propulsion system model of a conceptual electrified advanced geared turbofan engine suitable for propelling a single-aisle commercial aircraft. Included with the engine model is a controller that provides representative dynamic performance across a full operating envelop. The model is meant to facilitate research studies and promote collaboration. It is envisioned for use in concept exploration studies, technology impact studies, and dynamics and controls studies. The engine model can be run in various modes of operation including boost and power extraction. It also has options for other electrification features and methods for engine shaft and electric machine integration. This paper documents the AGTF30-e and illustrates its use through various simulation scenarios.

AGTF30-e↗
NASA NTRSDate not supplied

The Advanced Geared Turbofan 30,000 lbf – electrified (AGTF30-e): A Virtual Testbed for Electrified Aircraft Propulsion Research

Electrified Aircraft Propulsion (EAP) is a growing topic of research with the potential to shape the future of commercial air travel. Here, detailed mathematical models serve an essential role in developing understanding and evaluating different technologies and design concepts. The Advanced Geared Turbofan 30,000 lbf – electrified (AGTF30-e) is an open-source software package developed by the National Aeronautics and Space Administration (NASA). The AGTF30-e provides a realistic propulsion system model of a conceptual electrified advanced geared turbofan engine suitable for propelling a single-aisle commercial aircraft. Included with the engine model is a controller that provides representative dynamic performance across a full operating envelop. The model is meant to facilitate research studies and promote collaboration. It is envisioned for use in concept exploration studies, technology impact studies, and dynamics and controls studies. The engine model can be run in various modes of operation including boost and power extraction. It also has options for other electrification features and methods for engine shaft and electric machine integration. This paper documents the AGTF30-e and illustrates its use through various simulation scenarios.

AGTF30-e↗
NASA NTRS1993

Evaluation of the Munich Method for modeling rocket engine performance

A new procedure, dubbed the Munich Method, has been proposed recently for the modeling of rocket engine performance. The author of the Munich Method claims it to be an extension and improvement of the thermodynamic procedures used to model rocket engines in the NASA-Lewis chemical equilibrium program. An examination of the Munich Method shows that it contains several flaws. If these defects are corrected then the Munich Method will produce results identical to those generated by the NASA-Lewis Code.

Zeleznik, Frank J.↗
NASA NTRSDate not supplied

Presenting Model-Based Systems Engineering Information to Non-Modelers

NASA’s Human Research Program’s (HRP) Exploration Medical Capability (ExMC) Element adopted Systems Engineering (SE) principles and Model Based Systems Engineering (MBSE) tools to capture the system functions, system architecture, requirements, interfaces, and clinical capabilities for a future exploration medical system. There are many different stakeholders who may use the information in the model: systems engineers, requirement engineers, clinicians (doctors, nurses, and pharmacists), scientists, and program managers. Many of these individuals do not have access to MBSE modeling toolsor have never used these tools. Many of these individuals (clinicians, scientists, even program managers)may have no experience with SE in general let alone interpreting a systems model. The challenge faced by ExMC was how to present the content in the model to non-modelers in a way they could understand with limited to no training in MBSE or the Systems Modeling Language (SysML) without using the modeling tool. Therefore, from the model, ExMC created an HTML report that is accessible to anyone with a browser. When creating the HTML report, the ExMC SE team talked to stakeholders and received their feedback on what content they wanted and how to display this content. Factoring in feedback, the report arranges the content in a way that not only directs readers through the SE process taken to derive the requirements, but also helps them to understand the fundamental steps in an SE approach. The report includes links to source information (i.e., NASA documentation that describes levels of care) and other SE deliverables (e.g., Concept of Operations). These links were provided to aid in the understanding of how the team created this content through a methodical SE approach. This paper outlines the process used to develop the model, the data chosen to share with stakeholders, many of the model elements used in the report, the review process stakeholders followed, the comments received from the stakeholders, and the lessons ExMC learned through producing this HTML report.

Jeff Cohen↗
NASA NTRSDate not supplied

Presenting Model-Based Systems Engineering Information to Non-Modelers

NASA’s Human Research Program’s (HRP) Exploration Medical Capability (ExMC) Element adopted Systems Engineering (SE) principles and Model Based Systems Engineering (MBSE) tools to capture the system functions, system architecture, requirements, interfaces, and clinical capabilities for a future exploration medical system. There are many different stakeholders who may use the information in the model: systems engineers, clinicians (physicians, nurses, and pharmacists), scientists, and program managers. Many of these individuals do not have access to MBSE modeling tools or have never used these tools. Many of these individuals (clinicians, scientists, even program managers) may have no experience with SE in general let alone interpreting a systems model. The challenge faced by ExMC was how to present the content in the model to non-modelers in a way they could understand with limited to no training in MBSE or the Systems Modeling Language (SysML) without using the modeling tool. Therefore, from the model, ExMC created an HTML report that is accessible to anyone with a browser. When creating the HTML report, the ExMC SE team talked to stakeholders and received their feedback on what content they wanted and how to display this content. Factoring in feedback, the report arranges the content in a way that not only directs readers through the SE process taken to derive the requirements, but also helps them to understand the fundamental steps in an SE approach. The report includes links to source information (i.e., NASA documentation that describes levels of care) and other SE deliverables (e.g., Concept of Operations). These links were provided to aid in the understanding of how the team created this content through a methodical SE approach. This paper outlines the process used to develop the model, the data chosen to share with stakeholders, many of the model elements used in the report, the review process stakeholders followed, the comments received from the stakeholders, and the lessons ExMC learned through producing this HTML report.1Trade names and trademarks are used in this report for identification only. Their usage does not constitute an official endorsement, either expressed or implied, by the National Aeronautics and Space Administration.

Jeffrey R. Cohen↗
NASA NTRSDate not supplied

Presenting Model-Based Systems Engineering Information to Non-Modelers

NASA’s Human Research Program’s (HRP) Exploration Medical Capability (ExMC) Element adopted Systems Engineering (SE) principles and Model Based Systems Engineering (MBSE) tools to capture the system functions, system architecture, requirements, interfaces, and clinical capabilities for a future exploration medical system. There are many different stakeholders who may use the information in the model: systems engineers, clinicians (physicians, nurses, and pharmacists), scientists, and program managers. Many of these individuals do not have access to MBSE modeling tools or have never used these tools. Many of these individuals (clinicians, scientists, even program managers) may have no experience with SE in general let alone interpreting a systems model. The challenge faced by ExMC was how to present the content in the model to non-modelers in a way they could understand with limited to no training in MBSE or the Systems Modeling Language (SysML) without using the modeling tool. Therefore, from the model, ExMC created an HTML report that is accessible to anyone with a browser. When creating the HTML report, the ExMC SE team talked to stakeholders and received their feedback on what content they wanted and how to display this content. Factoring in feedback, the report arranges the content in a way that not only directs readers through the SE process taken to derive the requirements, but also helps them to understand the fundamental steps in an SE approach. The report includes links to source information (i.e., NASA documentation that describes levels of care) and other SE deliverables (e.g., Concept of Operations). These links were provided to aid in the understanding of how the team created this content through methodical SE approach. This paper outlines the process used to develop the model, the data chosen to share with stakeholders, many of the model elements used in the report, the review process stakeholders followed, the comments received from the stakeholders, and the lessons ExMC learned through producing this HTML report.

Jeffrey R. Cohen↗