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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1947

Investigation of 10-Stage Axial-Flow X24C-2 Compressor: Performance at Inlet Pressure of 21 Inches Mercury Absolute and Inlet Temperature of 538 R - 1

The performance at inlet pressure of 21 inches mercury absolute and inlet temperature of 538 R for the 10-stage axial-flow X24C-2 compressor from the X24C-2 turbojet engine was investigated. the peak adiabatic temperature-rise efficiency for a given speed generally occurred at values of pressure coefficient fairly close to 0.35.For this compressor, the efficiency data at various speeds could be correlated on two converging curves by the use of a polytropic loss factor derived.

Schum, Harold J.↗
NASA NTRS1948

Altitude-Wind-Tunnel Investigation of a 4000-Pound-Thrust Axial-Flow Turbojet Engine: Performance Characteristics with the High-Flow Compressor - 3

A wind tunnel investigation was conducted to determine the performance of a 4000-pound-thrust axial-flow turbojet engine with a high flow compressor. Pressure altitudes included 5000 to 40000 feet with ram pressure ratios from 1.00 to 1.82. Altitudes included 20000 to 40000 feet and ram pressure ratios from 1.09 to 1.75. A comparison is made between engine performance with high flow and low flow compressors.

Fleming, William A.↗
NASA NTRS2003

Design and Development of an air-cooled Temperature-Swing Adsorption Compressor for Carbon Dioxide

The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. We have a developed a temperature-swing adsorption compressor (TSAC) for performing these tasks that is energy efficient, quiet, and has no wearing parts. This paper discusses the design features of a TSAC hardware that uses air as the cooling medium and has Space Station application.

Mulloth, Lila M.↗
NASA NTRS2003

Integrated Testing of a Carbon Dioxide Removal Assembly and a Temperature-Swing Adsorption Compressor for Closed-Loop Air Revitalization

Accumulation and subsequent compression of carbon dioxide that is removed from space cabin are two important processes involved in a closed-loop air revitalization scheme of the International Space Station (ISS). The carbon dioxide removal assembly (CDRA) of ISS currently operates in an open loop mode without a compressor. This paper describes the integrated test results of a flight-like CDRA and a temperature-swing adsorption compressor (TSAC) for carbon dioxide removal and compression. The paper provides details of the TSAC operation at various CO2 loadings and corresponding performance of CDRA.

Knox, J. C.↗
NASA NTRS2004

Air-Cooled Design of a Temperature-Swing Adsorption Compressor for Closed-Loop Air Revitalization Systems

The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. We have a developed a temperature-swing adsorption compressor (TSAC) for performing these tasks that is energy efficient, quiet, and has no rapidly moving parts. This paper discusses the mechanical design and the results of thermal model validation tests of a TSAC that uses air as the cooling medium.

Mulloth, Lila M.↗
NASA NTRS1949

Performance of J33-A-27 Turbojet-Engine Compressor: Center for Infrastructure Engineering Studies - 1

The J33-A-27 compressor was operated at an inlet pressure of 14 inches of mercury absolute and ambient inlet temperature over a range of equivalent impeller speeds from 6100 to 11,800 rpm. At the design equivalent speed of 11,800 rpm, the J33-A-27 compressor had a peak pressure ratio of 4.40 at an equivalent weight flow of 105.7 pounds per second and a peak adiabatic temperature-rise efficiency of 0.745. The maximum equivalent weight flow at design speed was 113.5 pounds per second.

Kovach, Karl↗
NASA NTRS1997

Wavelet Methods Developed to Detect and Control Compressor Stall

A "wavelet" is, by definition, an amplitude-varying, short waveform with a finite bandwidth (e.g., that shown in the first two graphs). Naturally, wavelets are more effective than the sinusoids of Fourier analysis for matching and reconstructing signal features. In wavelet transformation and inversion, all transient or periodic data features (as in compressor-inlet pressures) can be detected and reconstructed by stretching or contracting a single wavelet to generate the matching building blocks. Consequently, wavelet analysis provides many flexible and effective ways to reduce noise and extract signals which surpass classical techniques - making it very attractive for data analysis, modeling, and active control of stall and surge in high-speed turbojet compressors. Therefore, fast and practical wavelet methods are being developed in-house at the NASA Lewis Research Center to assist in these tasks. This includes establishing user-friendly links between some fundamental wavelet analysis ideas and the classical theories (or practices) of system identification, data analysis, and processing.

Le, Dzu K.↗
NASA NTRS1997

Compressor Case Manufactured Using High-Temperature Polyimides

High-temperature polymer composites (PMC's) offer lighter weight and higher specific strengths than titanium alloys for advanced aircraft engine applications-especially in fan and compressor components, where temperatures do not exceed 550 F (288 C). VCAP, a polyimide resin developed at the NASA Lewis Research Center, was filament wound at Lincoln Composites in Lincoln, Nebraska, with graphite and glass fibers to produce a lightweight compressor case for an Integrated High Performance Turbine Engine Technology (IHPTET) engine. This engine application requires a PMC that can withstand air pressures (60 psi) and temperatures exceeding the degradation limits of other high-temperature polyimides, such as PMR-15.

Sutter, James K.↗
NASA NTRS2005

Closed Loop Active Flow Separation Detection and Control in a Multistage Compressor

Active closed loop flow control was successfully demonstrated on a full annulus of stator vanes in a low speed axial compressor. Two independent methods of detecting separated flow conditions on the vane suction surface were developed. The first technique detects changes in static pressure along the vane suction surface, while the second method monitors variation in the potential field of the downstream rotor. Both methods may feasibly be used in future engines employing embedded flow control technology. In response to the detection of separated conditions, injection along the suction surface of each vane was used. Injected mass flow on the suction surface of stator vanes is known to reduce separation and the resulting limitation on static pressure rise due to lowered diffusion in the vane passage. A control algorithm was developed which provided a proportional response of the injected mass flow to the degree of separation, thereby minimizing the performance penalty on the compressor system.

Bright, Michelle M.↗
NASA NTRS2004

Active Closed-Loop Stator Vane Flow Control Demonstrated in a Low-Speed Multistage Compressor

Closed-loop flow control was successfully demonstrated on the surface of stator vanes in NASA Glenn Research Center's Low-Speed Axial Compressor (LSAC) facility. This facility provides a flow field that accurately duplicates the aerodynamics of modern highly loaded compressors. Closed-loop active flow control uses sensors and actuators embedded within engine components to dynamically alter the internal flow path during off-nominal operation in order to optimize engine performance and maintain stable operation.

Bright, Michelle M.↗
NASA NTRS2005

Impulsive Injection for Compressor Stator Separation Control

Flow control using impulsive injection from the suction surface of a stator vane has been applied in a low speed axial compressor. Impulsive injection is shown to significantly reduce separation relative to steady injection for vanes that were induced to separate by an increase in vane stagger angle of 4 degrees. Injected flow was applied to the airfoil suction surface using spanwise slots pitched in the streamwise direction. Injection was limited to the near-hub region, from 10 to 36 percent of span, to affect the dominant loss due to hub leakage flow. Actuation was provided externally using high-speed solenoid valves closely coupled to the vane tip. Variations in injected mass, frequency, and duty cycle are explored. The local corrected total pressure loss across the vane at the lower span region was reduced by over 20 percent. Additionally, low momentum fluid migrating from the hub region toward the tip was effectively suppressed resulting in an overall benefit which reduced corrected area averaged loss through the passage by 4 percent. The injection mass fraction used for impulsive actuation was typically less than 0.1 percent of the compressor through flow.

Culley, Dennis E.↗
NASA NTRS2005

ICER-3D: A Progressive Wavelet-Based Compressor for Hyperspectral Images

ICER-3D is a progressive, wavelet-based compressor for hyperspectral images. ICER-3D is derived from the ICER image compressor. ICER-3D can provide lossless and lossy compression, and incorporates an error-containment scheme to limit the effects of data loss during transmission. The three-dimensional wavelet decomposition structure used by ICER-3D exploits correlations in all three dimensions of hyperspectral data sets, while facilitating elimination of spectral ringing artifacts. Correlation is further exploited by a context modeler that effectively exploits spectral dependencies in the wavelet-transformed hyperspectral data. Performance results illustrating the benefits of these features are presented.

Kiely, A.↗
NASA NTRS2006

Integrated Testing of a 4-Bed Molecular Sieve, Air-Cooled Temperature Swing Adsorption Compressor, and Sabatier Engineering Development Unit

Accumulation and subsequent compression of carbon dioxide that is removed from the space cabin are two important processes involved in a closed-loop air revitalization scheme of the International Space Station (ISS). The 4-Bed Molecular Sieve (4BMS) of ISS currently operates in an open loop mode without a compressor. The Sabatier Engineering Development Unit (EDU) processes waste CO2 to provide water to the crew. This paper reports the integrated 4BMS, air-cooled Temperature Swing Adsorption Compressor (TSAC), and Sabatier EDU testing. The TSAC prototype was developed at NASA Ames Research Center (ARC). The 4BMS was modified to a functionally flight-like condition at NASA Marshall Space Flight Center (MSFC). Testing was conducted at MSFC. The paper provides details of the TSAC operation at various CO2 loadings and corresponding performance of the 4BMS and Sabatier.

Knox, James C.↗
NASA NTRS1985

Variable geometry device for turbine compressor outlet

A variable geometry device is provided for use with the compressor outlet of a turbine engine. The turbine engine includes a support housing, a compressor contained within the support housing and having a compressed air outlet and in which a pair of spaced walls define an annular and radially extending diffuser passageway. The inner end of the diffuser passageway is open to the compressed outlet while the outer end of the diffuser passageway is open to the combustion chamber for the turbine engine. A plurality of circumferentially spaced diffuser vanes are mounted to one of the diffuser walls and protrude across the diffuser passageway. An annular recessed channel is formed around the opposite diffuser wall and an annular ring is mounted within the channel. A motor is operatively connected to this ring and, upon actuation, displaces the ring transversely across the diffuser passageway to variably restrict the diffuser passageway. In addition, the ring includes a plurality of slots which register with the diffuser vanes so that the vane geometry remains the same despite axial displacement of the ring.

Rogo, Casimir↗
NASA NTRS2008

Devices and methods of operation thereof for providing stable flow for centrifugal compressors

Centrifugal compressor flow stabilizing devices and methods of operation thereof are disclosed that act upon the flow field discharging from the impeller of a centrifugal compressor and modify the flow field ahead of the diffuser vanes such that flow conditions contributing to rotating stall and surge are reduced or even eliminated. In some embodiments, shaped rods and methods of operation thereof are disclosed, whereas in other embodiments reverse-tangent air injection devices and methods are disclosed.

Skoch, Gary J.↗
NASA NTRS1949

Preliminary Analysis of Axial-Flow Compressors Having Supersonic Velocity at the Entrance of the Stator

A supersonic compressor design having supersonic velocity at the entrance of the stator is analyzed on the assumption of two-dimensional flow. The rotor and stator losses assumed in the analysis are based on the results of preliminary supersonic cascade tests. The results of the analysis show that compression ratios per stage of 6 to 10 can be obtained with adiabatic efficiency between 70 and 80 percent. Consideration is also given in the analysis to the starting, stability, and range of efficient performance of this type of compressor. The desirability of employing variable-geometry stators and adjustable inlet guide vanes is indicated. Although either supersonic or subsonic axial component of velocity at the stator entrance can be used, the cascade test results suggest that higher pressure recovery can be obtained if the axial component is supersonic.

Ferri, Antonio↗
NASA NTRS1949

Performance of Axial-Flow Supersonic Compressor of XJ55-FF-1 Turbojet Engine. II - Performance of Inlet Guide Vanes as Separate Component

The inlet wide vanes for the supersonic compressor of the XJ55-FF-1 engine were studied as a separate component in order to determine the performance prior to installation in the compressor test rig. Turning angles approached design values, and increased approximately to through the inlet Mach number range from 0.30 to choke. A sharp break in turning angle was experienced when the choke condition was reached. The total-pressure loss through the guide vanes was approximately 1 percent for the unchoked conditions and from 5 to 6 percent when choked.

Graham, Robert C.↗