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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1958

Investigation of a Prototype Iroquois Turbojet Engine in an Altitude Test Chamber. COORD. NO. AF-P-6

Operation of the original engine configuration disclosed a severe compressor stall problem at high altitude, which was largely attributed to a radial flow distortion entering the high-pressure compressor. Engine modifications for eliminating or alleviating the stall problem were investigated. These included use of variable high-pressure compressor inlet guide vanes, increased turbine-stator areas, and minor alterations in both the low- and high-pressure compressor rotors.

McAuay, John E.↗
NASA NTRS1958

Some Altitude Operational Characteristics of a Prototype Iroquois Turbojet Engine. COORD. NO. AF-P-6

The evaluation of the altitude operational characteristics was part of the over-all investigation of the early developmental Iroquois engine. Engine steady-state windmilling characteristics were evaluated over a range of flight Mach numbers from 0.48 to 1.72 at altitudes of 35,000 and 50,000 feet. Engine altitude ignition limits were obtained over a range of flight Mach numbers from 0.5 to 1.5 with the standard engine ignition system and also with an oxygen boost system. A short investigation of high-speed altitude reignition following combustor blowout was conducted.

Peters, Daniel J.↗
NASA NTRS2007

Wireless Data-Acquisition System for Testing Rocket Engines

A prototype wireless data-acquisition system has been developed as a potential replacement for a wired data-acquisition system heretofore used in testing rocket engines. The traditional use of wires to connect sensors, signal-conditioning circuits, and data acquisition circuitry is time-consuming and prone to error, especially when, as is often the case, many sensors are used in a test. The system includes one master and multiple slave nodes. The master node communicates with a computer via an Ethernet connection. The slave nodes are powered by rechargeable batteries and are packaged in weatherproof enclosures. The master unit and each of the slave units are equipped with a time-modulated ultra-wide-band (TMUWB) radio transceiver, which spreads its RF energy over several gigahertz by transmitting extremely low-power and super-narrow pulses. In this prototype system, each slave node can be connected to as many as six sensors: two sensors can be connected directly to analog-to-digital converters (ADCs) in the slave node and four sensors can be connected indirectly to the ADCs via signal conditioners. The maximum sampling rate for streaming data from any given sensor is about 5 kHz. The bandwidth of one channel of the TM-UWB radio communication system is sufficient to accommodate streaming of data from five slave nodes when they are fully loaded with data collected through all possible sensor connections. TM-UWB radios have a much higher spatial capacity than traditional sinusoidal wave-based radios. Hence, this TM-UWB wireless data-acquisition can be scaled to cover denser sensor setups for rocket engine test stands. Another advantage of TM-UWB radios is that it will not interfere with existing wireless transmission. The maximum radio-communication range between the master node and a slave node for this prototype system is about 50 ft (15 m) when the master and slave transceivers are equipped with small dipole antennas. The range can be increased by changing to larger antennas and/or greater transmission power. The battery life of a slave node ranges from about six hours during operation at full capacity to as long as three days when the system is in a "sleep" mode used to conserve battery charge during times between setup and rocket-engine testing. Batteries can be added to prolong operational lifetimes. The radio transceiver dominates the power consumption.

Lin, Chujen↗
NASA NTRS1993

A prototype stable RNA identification cassette for monitoring plasmids of genetically engineered microorganisms

A prototype stable RNA identification cassette for monitoring genetically engineered plasmids carried by strains of Escherichia coli has been developed. The cassette consists of a Vibrio proteolyticus 5S ribosomal RNA (rRNA) gene surrounded by promoters and terminators from the rrnB operon of Escherischia coli. The identifier RNA is expressed and successfully processed so that approximately 30% of the 5S rRNA isolated from either whole cells or 70S ribosomes is of the V. proteolyticus type. Cells carrying the identifier are readily detectable by hybridization. Accurate measurements show that the identification cassette has little effect on fitness compared to a strain containing an analogous plasmid carrying wild type E. coli 5S rRNA, and the V. proteolyticus 5S rRNA gene is not inactivated after prolonged growth. These results demonstrate the feasibility of developing small standardized identification cassettes that can utilize already existing highly sensitive rRNA detection methods. Cassettes of this type could in principle be incorporated into either the engineered regions of recombinant plasmids or their hosts.

Non-NASA Center↗
DOE OSTI2018

Effects of NOX Storage Component on Ammonia Formation in TWC for Passive SCR NOX Control in Lean Gasoline Engines

A prototype three-way catalyst (TWC) with NOX storage component was evaluated for ammonia (NH3) generation on a 2.0-liter BMW lean burn gasoline direct injection engine as a component in a passive ammonia selective catalytic reduction (SCR) system. The passive NH3 SCR system is a potential approach for controlling nitrogen oxides (NOX) emissions from lean burn gasoline engines. In this system, NH3 is generated over a close-coupled TWC during periodic slightly-rich engine operation and subsequently stored on an underfloor SCR catalyst. Upon switching to lean, NOX passes through the TWC and is reduced by the stored NH3 on the SCR catalyst. Adding a NOX storage component to a TWC provides two benefits in the context of a passive SCR system: (1) enabling longer lean operation by storing NOX upstream and preserving NH3 inventory on the downstream SCR catalyst; and (2) increasing the quantity and rate of NH3 production during rich operation. Since the fuel penalty associated with passive SCR NOX control depends on the fraction of time that the engine is running rich rather than lean, both benefits (longer lean times and shorter rich times achieved via improved NH3 production) will decrease the passive SCR fuel penalty. However, these benefits are primarily realized at low to moderate temperatures (300-500 °C), where the NOX storage component is able to store NOX, with little to no benefit at higher temperatures (>500 °C), where NOX storage is no longer effective. This study discusses engine parameters and control strategies affecting the NH3 generation over a TWC with NOX storage component.

Prikhodko, Vitaly↗
NASA NTRS1989

UHB demonstrator interior noise control flight tests and analysis

The measurement and analysis of MD-UHB (McDonnell Douglas Ultra High Bypass) Demonstrator noise and vibration flight test data are described as they relate to passenger cabin noise. The analyses were done to investigate the interior noise characteristics of advanced turboprop aircraft with aft-mounted engines, and to study the effectiveness of selected noise control treatments in reducing passenger cabin noise. The UHB Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB engine. For these tests, the UHB engine was a General Electric Unducted Fan, with either 8x8 or 10x8 counter-rotating propeller configurations. Interior noise level characteristics were studied for several altitudes and speeds, with emphasis on high altitude (35,000 ft), high speed (0.75 Mach) cruise conditions. The effectiveness of several noise control treatments was evaluated based on cabin noise measurements. The important airborne and structureborne transmission paths were identified for both tonal and broadband sources using the results of a sound intensity survey, exterior and interior noise and vibration data, and partial coherence analysis techniques. Estimates of the turbulent boundary layer pressure wavenumber-frequency spectrum were made, based on measured fuselage noise levels.

Simpson, M. A.↗
NASA NTRS1981

Development of a solar receiver for an organic Rankine cycle engine

A prototype power conversion assembly (PCA) developed by an American aerospace company is considered. The PCA will be mounted at the focal point of a 12 meter parabolic dish and will produce approximately 20 kW of 3 kHz ac power to a ground-mounted rectifier. The PCA includes a cavity receiver coupled to an organic Rankine cycle engine. The engine working fluid is toluene. The performance goals of the receiver design are to maximize both the thermal efficiency and the heat capacity of the core. The latter goal is desired for stabilizing the PCA operation during intermittent cloud cover. The receiver design is based upon the utilization of a direct-heated copper shell. It was necessary to develop a feasible manufacturing process for assuring a good braze joint between the stainless steel, containing the toluene, and the copper shell.

Haskins, H. J.↗
NASA NTRS1990

Software engineering activities at SEI (Software Engineering Institute)

Prototyping was shown to ease system specification and implementation, especially in the area of user interfaces. Other prototyping approaches do not allow for the evolution of the prototype into a production system or support maintenance after the system is fielded. A set of goals is presented for a modern user interface environment and Serpent, a prototype implementation that achieves these goals, is described.

Chittister, Clyde↗
NASA NTRS1970

Thermodynamics of the internal combustion engine

The ubiquitous automobile has played both the role of hero and villain during the course of its history. At the present time it is being cast as the villain with increasing frequency because it has been indicted as a major source of air pollution. It is just this characterization that is responsible for our renewed interest in the automobile. When we speak of the automobile as a source of air pollution, we really mean the heart of the automobile, the internal combustion engine. The prototype of the modern internal combustion engine was first successfully operated by Nicholas August Otto in 1876. In spite of its long history, the internal combustion engine is still poorly understood in terms of the details of the physical processes that take place during its operations. The internal combustion engine operates on what is known as the Otto cycle, and Otto cycle calculations have been with us for many years. The emphasis in earlier calculations was usually on the performance rather than on the pollution aspects. Performance characteristics can often be estimated reasonably accurately even with a considerable degree of simplification. We are interested in the pollution aspects of the internal combustion engine, and therefore the calculations must be performed with more care. Our extensive experience with equilibrium calculations places us in a position to carry out such careful calculations. We have just recently begun such an analysis, and its objective is the prediction of exhaust gas properties. I will describe our progress by first reviewing the Otto cycle, and then I will illustrate the effect of various assumptions on the calculated results.

Frank J. Zeleznik↗
NASA NTRS2020

Enabling Deep Space Science Missions with Nuclear Thermal Propulsion

Nuclear thermal propulsion (NTP) enables entirely new classes of deep-space science missions to yield scientific returns that, in most cases, are simply not possible with traditional architectures. NTP systems can yield dramatically reduced interplanetary travel times, deliver roughly 2- 3 times (or more) the mass that can be delivered by conventional chemical propulsion systems, or provide a combination of these advantages to further enhance scientific return. Present NASA and DoD-sponsored plans for NTP systems will mature the technology using prototype and flight demonstration engines to prove the designs. These prototype engines will have performance in the correct thrust range so as to permit use as a low-risk propulsion stage in support of high-payoff deep space science missions. Additionally, the use of low-enriched Uranium (LEU) fuels over highly-enriched Uranium (HEU) fuels reduce the costs of engine development, qualification, acceptance and launch, and lowers the risks associated with proliferation management.

Kurt A Polzin↗
NASA NTRS1953

Altitude Operational Characteristics of Prototype J40-WE-8 Turbojet Engine

The altitude operational characteristics of the prototype J40-WE-8 turbojet engine were determined in the NACA Lewis altitude wind tunnel. The operational characteristics that were obtained include (1) compressor surge characteristics, (2) acceleration and deceleration rates, (3) steady-state windmilling-engine characteristics, (4) altitude ignition characteristics, and (5) the effect of two grades of fuel on steady-state engine performance at an altitude of 45,000 feet and a flight Mach number of 0.20. The altitude ignition characteristics determined include the effects of (1) ignition fuel flow, (2) two ignition procedures, (3) fuel temperatures, and (4) two grades of fuel on ignition characteristics. The compressor surge line, when presented as a function of compressor pressure ratio and corrected engine speed, was not affected by changes in flight condition and was independent of engine-inlet installation and of the manner in which surge was approached, rapidly or slowly. Also there was no effect of altitude or engine-inlet installation on the compressor surge recovery line when presented as a function of compressor pressure ratio and corrected engine speed.

FUELS - RELATION TO ENGINE PERFORMANCE↗
NASA NTRS1951

Altitude Wind Tunnel Investigation of the Performance of Compressor, Combustor, and Turbine Components of Prototype J47D (RX1-1) Turbojet Engine

As a portion of an over-all performance investigation of the prototype J47D (RX-1) turbojet engine, performance of the compressor, combustor, and turbine components has been determined in the Lewis altitude wind tunnel over a range of altitude from 5000 to 55,000 feet and at flight Mach numbers from 0.19 to 0.92. Investigations were conducted with the engine operating on an electronic control schedule and slow with a two-lever control system by which fuel flow and exhaust-nozzle area could be controlled separately. Two combustor configurations were investigated.

ENGINES, TURBO-JET↗
NASA NTRS2003

COBRA System Engineering Processes to Achieve SLI Strategic Goals

The COBRA Prototype Main Engine Development Project was an endeavor conducted as a joint venture between Pratt & Whitney and Aerojet to conduct risk reduction in LOX/LH2 main engine technology for the NASA Space Launch Initiative (SLI). During the seventeen months of the project (April 2001 to September 2002), approximately seventy reviews were conducted, beginning with the Engine Systems Requirements Review (SRR) and ending with the Engine Systems Interim Design Review (IDR). This paper discusses some of the system engineering practices used to support the reviews and the overall engine development effort.

Ballard, Richard O.↗
NASA NTRS1951

Altitude-wind-tunnel Investigation of Performance Characteristics of a J47D Prototype (RX1-1) Turbojet Engine with Variable-area Exhaust Nozzle

Performance of a J47D (RX1-1) turbojet engine equipped with afterburner, variable-area exhaust nozzle, and integrated electronic control was determined over a range of flight conditions. These data were obtained with the electronic control both operative and inoperative. For operation with scheduled exhaust nozzle area, the minimum specific fuel consumption of 1.15 pounds of fuel per hour per pound of net thrust occurred at about 7200 rpm at altitudes from 5000 to 25,000 feet at a flight Mach number of 0.19.

ENGINES, TURBOJET↗
NASA NTRS1978

SIMS prototype system 1 test results: Engineering analysis

The space and domestic water solar heating system designated SIMS Prototype Systems 1 was evaluated. The test system used 720 ft (gross) of Solar Energy Products Air Collectors, a Solar Control Corporation SAM 20 Air Handler with Model 75-175 control unit, a Jackson Solar Storage tank with Rho Sigma Mod 106 controller, and 20 tons of rack storage. The test data analysis performed evaluates the system performance and documents the suitability of SIMS Prototype System 1 hardware for field installation.

Source record↗
NASA NTRS2002

Space Shuttle Main Engine (SSME) Options for the Future Shuttle

The main engines for the Future Shuttle will focus on improved safety and operability. Performance enhancements may also be required for vehicle safety purposes to achieve more desirable abort scenarios. This paper discusses the potential improvements that will be considered for implementation into the Future Shuttle. Integrated engine and vehicle health management systems will achieve additional system-level reliability improvements over those currently in development. Advanced instrumentation for detecting leaks, analyzing component wear and degradation, and providing sophisticated operational data will be used for reliable engine control and scheduling maintenance operations. A new nozzle and main combustion chamber (MCC) will reduce failure probability by 50% and allow for higher thrust capability without requiring the entire engine to be redesigned. Turbopump improvements may range from minor component improvements to using 3rd-generation pumps built on the advanced concepts demonstrated by the Integrated Powerhead Development (IPD) program and the Space Launch Initiative (SLI) prototype engines.The main engines for the Future Shuttle will focus on improved safety and operability. Performance enhancements may also be required for vehicle safety purposes to achieve more desirable abort scenarios. This paper discusses the potential improvements that will be considered for implementation into the Future Shuttle. Integrated engine and vehicle health management systems will achieve additional system-level reliability improvements over those currently in development. Advanced instrumentation for detecting leaks, analyzing component wear and degradation, and providing sophisticated operational data will be used for reliable engine control and scheduling maintenance operations. A new nozzle and main combustion chamber (MCC) will reduce failure probability by 50% and allow for higher thrust capability without requiring the entire engine to be redesigned. Turbopump improvements may range from minor component improvements to using 3rd-generation pumps built on the advanced concepts demonstrated by the Integrated Powerhead Development (IPD) program and the Space Launch Initiative (SLI) prototype engines.

Jue, Fred↗