Investigation of Air Bearings for Small High-Performance Aircraft Gas Turbines

1972 ◽  
Vol 94 (4) ◽  
pp. 294-302
Author(s):  
P. W. Curwen ◽  
W. E. Young ◽  
R. G. Furgurson
Keyword(s):  
Performance Studies ◽  
Gas Turbines ◽  
High Performance ◽  
Air Bearing ◽  
Test Results ◽  
Air Bearings ◽  
Propulsion Systems ◽  
And Performance ◽  
Turboshaft Engine ◽  
Engine Start

High temperatures and rotative speeds of future U. S. Army aircraft propulsion systems will impose increasingly severe operating requirements on oil-lubricated engine bearings and associated seals. Accordingly, air-lubricated bearings are being investigated as a possible approach to alleviating the lubrication problems. This paper presents the results of design and performance studies, as well as bearing component tests, relative to applying air bearings to a two-shaft, 3.5-lb/sec turboshaft engine. The test results verify that air bearings can carry the maximum loads imposed by flight and landing conditions, and can survive the sliding contacts associated with 15,000 engine start/stop cycles. Incentives for pursuing the air-bearing approach are identified, as are also the development and problem areas.

The Ballistic Air Cleaner Concept for Army Vehicular Gas Turbines

1968 ◽  
Author(s):  
L. J. DuRocher ◽  
Hugo Giannotti
Keyword(s):  
Boundary Layer ◽  
Gas Turbines ◽  
High Performance ◽  
The Novel ◽  
Air Cleaner ◽  
And Performance

The air cleaner requirements for Army vehicular gas turbines are developed and performance of the novel boundary-layer ballistic type separator is discussed. A unit specifically designed for gas turbines demonstrates high performance. This separator is compared and field results are included.

scholarly journals Use of the Brayton Cycle in Solar Electric Power Generation

1989 ◽  
Author(s):  
Dan Weiner ◽  
Giora Meron
Keyword(s):  
Gas Turbines ◽  
High Performance ◽  
Attractive Alternative ◽  
Brayton Cycle ◽  
Electric Generator ◽  
Central Receiver ◽  
System Components ◽  
Prime Movers ◽  
Turboshaft Engine ◽  
And Control

The utilization of gas turbines in a central receiver is an attractive alternative due to the ability of these prime movers to endure temperatures of about 2000°F while achieving high performance. In this paper the problems of modifying a 250 kW Allison Turboshaft Engine and its conversion into solar gas turbines are presented. The various solutions referring to the various system components, such as combustion chamber, hot pipeline, electric generator and control system are detailed.

Air bearings in high precision systems

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
I. Cracaoanu ◽  
F. Bremer
Keyword(s):  
Surface Topography ◽  
High Precision ◽  
Air Bearing ◽  
Test Results ◽  
Air Bearings ◽  
Bearing Surface ◽  
Operational Parameters ◽  
Low Friction ◽  
Air Supply ◽  
Precision System

In high precision system applications low friction levels between components are desirable. Moving heavy parts at high speeds and accelerations without friction is possible by using air bearings. The main failure ofthe air bearings is the wear phenomenon (modification of surface topography) that occurs due to crash into the counterpart when air supply is interrupted. The aim of this research is to investigate different types of air bearings for a large number of crashes using real operational parameters from the field: speed, acceleration, load and supply air pressure. The real crash phenomenon in a high precision machine hasbeen replicated using a test setup. During testing, evolution of air bearing surface topography and air bearing characteristics (gap and flow) after different number of crashes are investigated. Test results showthat some air bearings are not reaching the specified number of crashes due to large defects that occur on the bearing surface. Some specific relations were found between crash defects and parameters such asthe air gap size and the direct contact between opposing surfaces. The preferred type of air bearings shows good performance even above the maximum specified number of crashes. This behavior can be explainedby low friction level during crash tests between the opposing surfaces. The test results from this investigation produced a reliable candidate for air bearings in the high precision system application.

Influence of Metakaolin on Mechanical Properties of High-Performance Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1904-1909
Author(s):  
Bao Min Wang ◽  
Wei Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Equal Mass ◽  
Test Results ◽  
Optimum Temperature ◽  
Compressive Strength Of Concrete ◽  
And Performance

Kaolin is a material with broad sources and a low price. Metakaolin is made from kaolin which is calcined, finely ground at an optimum temperature of 750 being kept constant for 4 hours. High strength and performance concrete can be mixed from metakaolin as a substitute for equal mass cement. The influences of 5%, 10% and 15% metakaolin in substitution of equal cement masses were studied on the mechanical properties of high-performance concrete. The test results showed that the addition of metakaolin improved the cubic compressive strength, splitting tensile strength and flexural strength of HPC, among which the improvement in compressive strength was the most siginificant, and simultaneously, there was also an improvement in concrete toughness in a certain degree. The optimum content of metakaolin is 10% resulting in an increase of the cubic compressive strength of concrete by 8.3% correspondingly.

scholarly journals Government/Industry Partnership: A Revolutionary Approach in Global Leadership of Advanced Gas Turbines

1996 ◽  
Author(s):  
Sy A. Ali ◽  
Charles M. Zeh
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Performance ◽  
Lower Cost ◽  
Department Of Energy ◽  
Preliminary Design ◽  
Test Results ◽  
Societal Benefits ◽  
Environmental Requirements ◽  
Partnership Program

The U.S. Department of Energy (DOE) has established a government/industry partnership program to greatly improve the capabilities of U.S. gas turbine technology. A new and challenging program named the Advanced Turbine Systems Program (ATS) has been initiated by DOE. The technical and business objectives of this initiative are to challenge the bounds of high performance capabilities of gas turbines, meet stringent environmental requirements, and produce lower cost electric power and cogeneration steam. This program will also yield greater societal benefits through continued expansion of high skilled U.S. jobs and export of U.S. products world wide. A progress report on the ATS program pertaining to program status at DOE will be presented and reviewed in this paper. A preliminary design of an industrial advanced turbine system configuration will also be outlined in the paper. The technical challenges; advanced critical technologies incorporation, analytical and experimental solutions, and test results of an advanced gas turbine meeting the DOE goals will be described and discussed.

scholarly journals An Advanced Microturbine System with Water-Lubricated Bearings

2009 ◽  
Vol 2009 ◽  
pp. 1-12 ◽  
Author(s):  
Susumu Nakano ◽  
Tadaharu Kishibe ◽  
Tomoaki Inoue ◽  
Hiroyuki Shiraiwa
Keyword(s):  
Gas Turbines ◽  
High Performance ◽  
Unique Feature ◽  
Laboratory Evaluation ◽  
Air Cooling ◽  
Test Results ◽  
Air Turbine ◽  
Operation Test ◽  
Load Tests ◽  
Electrical Output

A prototype of the next-generation, high-performance microturbine system was developed for laboratory evaluation. Its unique feature is its utilization of water. Water is the lubricant for the bearings in this first reported application of water-lubricated bearings in gas turbines. Bearing losses and limitations under usage conditions were found from component tests done on the bearings and load tests done on the prototype microturbine. The rotor system using the water-lubricated bearings achieved stable rotating conditions at a rated rotational speed of 51,000 rpm. An electrical output of 135 kW with an efficiency of more than 33% was obtained. Water was also utilized to improve electrical output and efficiency through water atomizing inlet air cooling (WAC) and a humid air turbine (HAT). The operation test results for the WAC and HAT revealed the WAC and HAT operations had significant effects on both electrical output and electrical efficiency.

scholarly journals Review of State-of-the-Art Green Monopropellants: For Propulsion Systems Analysts and Designers

Aerospace ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 20
Author(s):  
Ahmed E. S. Nosseir ◽  
Angelo Cervone ◽  
Angelo Pasini
Keyword(s):  
Environmental Sustainability ◽  
Electric Propulsion ◽  
High Performance ◽  
Systems Design ◽  
Propulsion Systems ◽  
Space Applications ◽  
Analysis And Design ◽  
Research Activities ◽  
Systems Analysts ◽  
And Performance

Current research trends have advanced the use of “green propellants” on a wide scale for spacecraft in various space missions; mainly for environmental sustainability and safety concerns. Small satellites, particularly micro and nanosatellites, evolved from passive planetary-orbiting to being able to perform active orbital operations that may require high-thrust impulsive capabilities. Thus, onboard primary and auxiliary propulsion systems capable of performing such orbital operations are required. Novelty in primary propulsion systems design calls for specific attention to miniaturization, which can be achieved, along the above-mentioned orbital transfer capabilities, by utilizing green monopropellants due to their relative high performance together with simplicity, and better storability when compared to gaseous and bi-propellants, especially for miniaturized systems. Owing to the ongoing rapid research activities in the green-propulsion field, it was necessary to extensively study and collect various data of green monopropellants properties and performance that would further assist analysts and designers in the research and development of liquid propulsion systems. This review traces the history and origins of green monopropellants and after intensive study of physicochemical properties of such propellants it was possible to classify green monopropellants to three main classes: Energetic Ionic Liquids (EILs), Liquid NOx Monopropellants, and Hydrogen Peroxide Aqueous Solutions (HPAS). Further, the tabulated data and performance comparisons will provide substantial assistance in using analysis tools—such as: Rocket Propulsion Analysis (RPA) and NASA CEA—for engineers and scientists dealing with chemical propulsion systems analysis and design. Some applications of green monopropellants were discussed through different propulsion systems configurations such as: multi-mode, dual mode, and combined chemical–electric propulsion. Although the in-space demonstrated EILs (i.e., AF-M315E and LMP-103S) are widely proposed and utilized in many space applications, the investigation transpired that NOx fuel blends possess the highest performance, while HPAS yield the lowest performance even compared to hydrazine.

scholarly journals Design Features of the ГТД 8000 and ГТД 15000 Marine Gas Turbine Engines

1992 ◽  
Author(s):  
Victor I. Romanov
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Performance ◽  
Performance Data ◽  
Design And Technology ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Design Features ◽  
And Performance ◽  
New Generation

This paper describes design features and performance data of the ГТД 8000 and ГТД 15000 engines of new generation. The efficiency of these engines is 34–35% (simple cycle, ISO Conditions). The paper presents basic trends of design and technology improvements resulted in a high performance engine. Examples of new gas turbines application are shown.

scholarly journals Gas Turbine Development in Sweden After 1945: A Historical Review

1998 ◽  
Author(s):  
Kjell T. E. Thoren
Keyword(s):  
Gas Turbine ◽  
Air Force ◽  
Gas Turbines ◽  
High Speed ◽  
High Performance ◽  
Historical Review ◽  
Propulsion Systems ◽  
Hybrid Propulsion ◽  
History Of ◽  
Industrial Gas Turbine

The gas turbine development history of Sweden is exciting. By international comparison Sweden and its gas turbine manufacturers are small but can nevertheless claim periods with the worlds highest output, or highest efficiency large industrial gas turbine respectively. Sweden has always created its own military aircraft and fitting, high performance engines are developed in Sweden in license cooperation with large international manufacturers. The Swedish Air Force ranked number four in the world during the 60s. Pioneering contributions were also made with small gas turbines, such as high speed turbogenerators in hybrid propulsion systems for cars and trucks. Professionals know that gas turbine development success does not come easy. A lot of setbacks have to be mastered. The size of the crew is not always significant in the process.

Trace nanoanalysis

1994 ◽  
Vol 52 ◽  
pp. 940-941
Author(s):  
D. E. Newbury ◽  
R. D. Leapman
Keyword(s):  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Detection Efficiency ◽  
Volume Element ◽  
And Performance ◽  
Trace Constituents ◽  
Secondary Ion ◽  
Concentration Levels ◽  
Structure Properties

Trace constituents, which can be very loosely defined as those present at concentration levels below 1 percent, often exert influence on structure, properties, and performance far greater than what might be estimated from their proportion alone. Defining the role of trace constituents in the microstructure, or indeed even determining their location, makes great demands on the available array of microanalytical tools. These demands become increasingly more challenging as the dimensions of the volume element to be probed become smaller. For example, a cubic volume element of silicon with an edge dimension of 1 micrometer contains approximately 5×1010 atoms. High performance secondary ion mass spectrometry (SIMS) can be used to measure trace constituents to levels of hundreds of parts per billion from such a volume element (e. g., detection of at least 100 atoms to give 10% reproducibility with an overall detection efficiency of 1%, considering ionization, transmission, and counting).

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