scholarly journals Application of Foil Bearings to Turbomachinery Including Vertical Operation

1999 ◽  
Author(s):  
James F. Walton ◽  
Hooshang Heshmat
Keyword(s):  
Journal Bearing ◽  
Wide Spectrum ◽  
Turbine Engines ◽  
Vibrational Amplitude ◽  
Gas Turbine Engines ◽  
Foil Bearings ◽  
New Class ◽  
Compliant Surface ◽  
Actual Equipment ◽  
Bearing Design

A review is made of the function of compliant surface bearings in serving the needs of modern turbomachinery. This service extends over a wide spectrum of severe operational and environmental conditions such as extreme low and high temperatures, speeds over 100,000 rpm and the use of cryogenics as lubricants. The importance of using appropriate simulators that duplicate the actual equipment in evaluating the application of compliant bearings is demonstrated via two specific examples; one, a simulator to evaluate bearings for an air cycle machine and another for an advanced cryogenic device. In view of the known difficulties in using hydrodynamic bearings in vertical machines a new preloaded compliant journal bearing design is offered which performs as well with a vertically mounted shaft as it does in horizontal operation. In terms of the location of the first two rigid body criticals the test data show the compliant bearing’s vertical operation to be at most 15% lower than for the horizontal case whereas the maximum vibrational amplitude stayed the same for both modes of operation. This new class of hydrodynamic compliant surface journal bearings now makes possible development of oil-free machines capable of all attitude operation such as aircraft gas turbine engines undergoing severe pitch maneuvers or machines that must be operated vertically due to space constraints.

Application of Foil Bearings to Turbomachinery Including Vertical Operation

2002 ◽  
Vol 124 (4) ◽  
pp. 1032-1041 ◽  
Author(s):  
J. F. Walton ◽  
H. Hesmat
Keyword(s):  
Journal Bearing ◽  
Wide Spectrum ◽  
Turbine Engines ◽  
Vibrational Amplitude ◽  
Gas Turbine Engines ◽  
Foil Bearings ◽  
New Class ◽  
Compliant Surface ◽  
Actual Equipment ◽  
Bearing Design

A review is made of the function of compliant surface bearings in serving the needs of modern turbomachinery. This service extends over a wide spectrum of severe operational and environmental conditions such as extreme low and high temperatures, speeds over 100,000 rpm, and the use of cryogenics as lubricants. The importance of using appropriate simulators that duplicate the actual equipment in evaluating the application of compliant bearings is demonstrated via two specific examples; one, a simulator to evaluate bearings for an air cycle machine and another for an advanced cryogenic device. In view of the known difficulties in using hydrodynamic bearings in vertical machines a new preloaded compliant journal bearing design is offered which performs as well with a vertically mounted shaft as it does in horizontal operation. In terms of the location of the first two rigid-body criticals, the test data show the compliant bearing’s vertical operation to be at most 15 percent lower than for the horizontal case, whereas the maximum vibrational amplitude stayed the same for both modes of operation. This new class of hydrodynamic compliant surface journal bearings now makes possible development of oil-free machines capable of all attitude operation, such as aircraft gas turbine engines undergoing severe pitch maneuvers or machines that must be operated vertically due to space constraints.

Test Experience With Turbine-End Foil Bearing Equipped Gas Turbine Engines

1983 ◽  
Author(s):  
F. J. Suriano ◽  
R. D. Dayton ◽  
Fred G. Woessner
Keyword(s):  
Gas Turbine ◽  
Thermal Environment ◽  
Full Range ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Engine Test ◽  
Gas Generator ◽  
Turbine Engine ◽  
Foil Bearings ◽  
Foil Bearing

The Garrett Turbine Engine Company, a Division of the Garrett Corporation, authorized under Air Force Contract F33615-78-C-2044 and Navy Contract N00140-79-C-1294, has been conducting development work on the application of gas-lubricated hydrodynamic journal foil bearings to the turbine end of gas turbine engines. Program efforts are directed at providing the technology base necessary to utilize high-temperature foil bearings in future gas turbine engines. The main thrust of these programs was to incorporate the designed bearings, developed in test rigs, into test engines for evaluation of bearing and rotor system performance. The engine test programs included a full range of operational tests; engine thermal environment, endurance, start/stops, attitude, environmental temperatures and pressures, and simulated maneuver bearing loadings. An 88.9 mm (3.5-inch) diameter journal foil bearing, operating at 4063 RAD/SEC (38,800 rpm), has undergone test in a Garrett GTCP165 auxiliary power unit. A 44.4 mm (1.75-inch) diameter journal foil bearing, operating at 6545 RAD/SEC (62,500 rpm) has undergone test in the gas generator of the Garrett Model JFS190. This paper describes the engine test experience with these bearings.

On the Integration of Hot Foil Bearings Into Gas Turbine Engines: Theoretical Treatment

2019 ◽  
Author(s):  
Hooshang Heshmat ◽  
James F. Walton
Keyword(s):  
High Temperature ◽  
System Dynamics ◽  
High Performance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Structural Stiffness ◽  
Foil Bearings ◽  
Foil Bearing ◽  
High Temperature Operation ◽  
Bearing System

Abstract To achieve high power density Gas Turbine Engines (GTEs), R&D efforts have strived to develop machines that spin faster and run hotter. One method to achieve that goal is to use high temperature capable foil bearings. In order to successfully integrate these advanced foil bearings into GTE systems, a theoretical understanding of both bearing and rotor system integration is essential. Without a fundamental understanding and sound theoretical modeling of the foil bearing coupled with the rotating system such an approach would prove application efforts fruitless. It is hoped that the information provided in this paper will open up opportunistic doors to designs presently thought to be impossible. In this paper an attempt is made to describe how an advanced foil bearing is modeled for extreme high temperature operation in high performance turbomachinery including GTEs, Supercritical CO2 turbine generators and others. The authors present the advances in foil bearing capabilities that were crucial to achieving high temperature operation. Achieving high performance in a compliant foil bearing under the wide extremes of operating temperatures, pressures and speeds, requires a bearing system design approach that accounts for the highly interrelated compliant surface foil bearing elements such as: the structural stiffness and frictional characteristics of the underlying compliant support structure across the operating temperature and pressure spectrum; and the coupled interaction of the structural elements with the hydrodynamic pressure generation. This coupled elasto-hydrodynamic-Finite Element highly non-linear iterative methodology will be used by the authors to present a series of foil bearing design evaluations analyzing and modeling the foil bearing under extreme conditions. The complexity of the problem of achieving foil bearing system operation beyond 870°C (1600°F) requires as a prerequisite the attention to the tribological details of the foil bearing. For example, it is necessary to establish how both the frictional and viscous damping coefficient elements as well as the structural and hydrodynamic stiffness are to be combined. By combining these characteristics the influence of frictional coefficients of the elastic and an-elastic materials on bearing structural stiffness and hence the bearing effective coupled elasto-hydrodynamic stiffness coefficients will be shown. Given that the bearing dynamic parameters — stiffness and damping coefficients — play a major role in the control of system dynamics, the design approach to successfully integrate compliant foil bearings into complex rotating machinery systems operating in extreme environments is explored by investigating the effects of these types of conditions on rotor-bearing system dynamics. The proposed rotor/bearing model is presented to describe how system dynamics and bearing structural properties and operating characteristics are inextricably linked together in a manner that results in a series separate but intertwined iterative solutions. Finally, the advanced foil bearing modeling and formulation in connection with resulting rotor dynamics of the system will be carried out for an experimental GTE simulator test rig. The analytical results will be compared with the experiments as presented previously to demonstrate the effectiveness of the developed method in a real world application [1].

scholarly journals Ceramic Bearings for Use in Gas Turbine Engines

1989 ◽  
Vol 111 (1) ◽  
pp. 146-154 ◽  
Author(s):  
E. V. Zaretsky
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Wide Range ◽  
Rolling Element ◽  
Full Complement ◽  
Endurance Tests ◽  
Bearing Design ◽  
Government Laboratories

Three decades of research by U.S. industry and government laboratories have produced a vast array of data related to the use of ceramic rolling-element bearings and bearing components for aircraft gas turbine engines. Materials such as alumina, silicon carbide, titanium carbide, silicon nitride, and a crystallized glass ceramic have been investigated. Rolling-element endurance tests and analysis of full-complement bearings have been performed. Materials and bearing design methods have improved continuously over the years. This paper reviews a wide range of data and analyses with emphasis on how early NASA contributions as well as more recent data can enable the engineer or metallurgist to determine just where ceramic bearings are most applicable for gas turbines.

Ultra-High Temperature Compliant Foil Bearings: The Journey to 870°C and Application in Gas Turbine Engines — Experiment

2018 ◽  
Author(s):  
Hooshang Heshmat ◽  
James F. Walton ◽  
Brian D. Nicholson
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Foil Bearings ◽  
Wide Range ◽  
The U.S ◽  
Ultra High Temperature

In this paper, the authors present the results of recent developments demonstrating that ultra-high temperature compliant foil bearings are suitable for application in a wide range of high temperature turbomachinery including gas turbine engines, supercritical CO2 power turbines and automotive turbochargers as supported by test data showing operation of foil bearings at temperatures to 870°C (1600°F). This work represents the culmination of efforts begun in 1987, when the U.S. Air Force established and led the government and industry collaborative Integrated High Performance Turbine Engine Technology (IHPTET) program. The stated goal of IHPTET was to deliver twice the propulsion capability of turbine engines in existence at that time. Following IHPTET, the Versatile Affordable Advanced Turbine Engines (VAATE) program further expanded on the original goals by including both versatility and affordability as key elements in advancing turbine engine technology. Achieving the stated performance goals would require significantly more extreme operating conditions including higher temperatures, pressures and speeds, which in turn would require bearings capable of sustaining temperatures in excess of 815°C (1500°F). Similarly, demands for more efficient automotive engines and power plants are subjecting the bearings in turbochargers and turbogenerators to more severe environments. Through the IHPTET and VAATE programs, the U.S. has made considerable research investments to advancing bearing technology, including active magnetic bearings, solid and vapor phase lubricated rolling element bearings, ceramic/hybrid ceramic bearings, powder lubricated bearings and compliant foil gas bearings. Thirty years after the IHPTET component goal of developing a bearing capable of sustained operation at temperatures above 540°C and potentially as high as 815°C (1500°F) recent testing has demonstrated achievement of this goal with an advanced, ultra-high temperature compliant foilgas bearing. Achieving this goal required a combination of high temperature foil material, a unique elastic-tribo-thermal barrier coating (KOROLON 2250) and a self-adapting compliant configuration. The authors describe the experimental hardware designs and design considerations of the two differently sized test rigs used to demonstrate foil bearings operating above 815°C (1500°F). Finally, the authors present and discuss the results of testing at temperatures to 870°C (1600°F).

Dynamic Stiffness and Damping of Foil Bearings for Gas Turbine Engines

1993 ◽  
Author(s):  
Walter L. Meacham ◽  
R. M. Fred Klaass ◽  
Ron Dayton ◽  
Ed Durkin
Keyword(s):  
Gas Turbine ◽  
Dynamic Stiffness ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Foil Bearings ◽  
Stiffness And Damping

Foil Air Bearings Cleared to Land

1998 ◽  
Vol 120 (07) ◽  
pp. 78-80 ◽  
Author(s):  
Giri L. Agrawal
Keyword(s):  
Gas Turbine ◽  
General Aviation ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Air Bearings ◽  
Ground Vehicles ◽  
Foil Bearings ◽  
Cooling Flow ◽  
Auxiliary Power ◽  
Auxiliary Power Units

This article explores use of foil air bearings in land-based turbomachinery. A machine with foil air bearings is more reliable than one with rolling element bearings because it requires fewer parts to support the rotative assembly and needs no lubrication. Foil air bearings can handle severe environmental conditions such as the ingestion of sand and dust. A reversed pilot design at the cooling flow inlet prevents large particles from entering the bearing's flow path, and smaller particles are continually flushed out of the bearing by the cooling flow. Many applications of foil air/gas bearings other than air cycle machines have been built and successfully tested, but nothing appears to be currently in production. Foil bearings have strong potential in several applications. Among these are small general aviation gas turbine engines; oil-free cryogenic turboexpanders for gas separation plants; auxiliary power units for various aerospace and ground vehicles; and, taking advantage of automated manufacturing methods, automotive gas turbine engines, vapor-cycle centrifugal compressors, and commercial air/gas compressors.

An Experimental and Theoretical Study of Dynamic Structural Stiffness in Compliant Foil Bearings

1993 ◽  
Author(s):  
C.-P. Roger Ku
Keyword(s):  
Dynamic Characteristics ◽  
High Performance ◽  
Operating Conditions ◽  
Design Parameters ◽  
Structural Stiffness ◽  
Static Loads ◽  
Foil Bearings ◽  
Compliant Surface ◽  
Wide Range ◽  
Bearing Design

Abstract This paper describes an experimental investigation into the dynamic characteristics of corrugated foil (bump foil) strips used in compliant surface foil bearings. This study provided the first opportunity to quantify the dynamic structural stiffness of bump foil strips for a wide range of operating conditions. The experimental data were compared to results obtained by a theoretical model developed earlier, and the comparisons show very good agreement. The effects of bearing design parameters, such as static loads, dynamic displacement amplitudes, bump configurations, pivot locations, surface coatings, and lubricant were also evaluated. An understanding of the dynamic characteristics of bump foil strips resulting from this work offers designers a means for enhancing the design of high-performance compliant foil bearings.

Prospects for Application of Ship’s Multi-Module Gas Turbine Engines on the Basis of Ceramic Tunnel Turbomachines

2011 ◽  
Author(s):  
A. V. Sudarev ◽  
A. A. Suryaninov ◽  
V. G. Konakov
Keyword(s):  
Wide Spectrum ◽  
Turbine Engines ◽  
Thermal Engineering ◽  
Gas Turbine Engines ◽  
Design Concepts ◽  
Module Design ◽  
Engine Efficiency ◽  
Innovative Materials ◽  
Notable Increase ◽  
Engineering Parameters

Analysis of thermodynamic and thermal-engineering parameters of GTE for mercantile and naval marines was conducted. A conclusion was made that GTEs designed specially for application under sea conditions have the highest efficiency. This is the 36–37% efficiency for simple cycle GTEs. With application of the complex cycle, a notable increase in the engine efficiency could be attained, particularly, by use of structural ceramics (SCMs) on the basis of innovative materials and some novel technological and design concepts. It permits to raise the engine efficiency up to 50% even with the net power of 300–500 kW. Results of numerical calculations for single unit and thirty two module GTEs demonstrated as follows. With the same baseline conditions, a multi-module unit has the volume which is more than twice less and the mass more than five times lower. Though when the number of GTE modules still further increases, decreasing of the turbomachine efficiency becomes a negative factor. To compensate it, it is required to increase the air heater regeneration ratio, to apply helical-channel turbomachines made of heat resistant SCMs, etc. Advantages of multi-module GTEs are evident. Thus, the mean efficiency of a machine during its lifetime increases. The handling independency increases, too. A need in outages to repair machines is eliminated. The control, governing and protection systems become simpler. The fire- and explosion safety increases. In fact, all the designing procedure now reduces to identification of the module number under conditions specified and within a space targeted. As opposed to a conventional ship’s GTE design with the engine having only a single electric net power generator, the multi-module design allows a fast implementation of the entire wide spectrum of operation duties required.

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