A Foil Thrust Bearing Test Rig for Evaluation of High Temperature Performance and Durability

Author(s):  
Brian D. Dykas ◽  
Daniel W. Tellier
Author(s):  
Thomas E. Russell ◽  
Crystal Heshmat ◽  
Dennis Locke

A novel, high-speed, high temperature, oil-free, foil thrust bearing test rig has been developed with a critical element being a double-acting, active magnetic thrust bearing. The magnetic thrust bearing is used to react against loads applied to the foil thrust bearing under test. The magnetic bearing has the capability of reacting against thrust loads of up to 2224 N (500 pounds) at speeds to 80,000 rpm, while the rotor is supported by foil journal bearings. Two issues that are especially challenging for this test rig are magnetic material selection and the electronic control system. The magnetic material selection is critical due to the high centrifugal stresses that occur at 80,000 rpm. The electronic control system must handle the non-linear variation in stiffness and damping that is seen by the magnetic thrust bearing as the foil thrust bearing is loaded, as well as maintain rotor system stability as the foil bearing is purposefully overloaded to the point of failure to discover maximum load and performance capabilities. This paper describes the design of the active magnetic thrust bearing, the material selection process, and the development of a digital signal processor based control system. Typical experimental data obtained during operation of the test rig will also be presented.


Author(s):  
Jason Wilkes ◽  
Ryan Cater ◽  
Erik Swanson ◽  
Kevin Passmore ◽  
Jerry Brady

Abstract This paper will show the influence of ambient pressure on the thrust capacity of bump-foil and spiral-groove gas thrust bearings. The bearings were operating in nitrogen at various pressures up to 69 bar, and were tested to failure. Failure was detected at various pressures by incrementally increasing the thrust load applied to the thrust bearing until the bearing was no longer thermally stable, or until contact was observed by a temperature spike measured by thermocouples within the bearing. These tests were performed on a novel thrust bearing test rig that was developed to allow thrust testing at pressures up to 207 bar cavity pressure at 260°C while rotating at speeds up to 120,000 rpm. The test rig floats on hydrostatic air bearings to allow for the direct measurement of applied thrust load through linkages that connect the stationary thrust loader to the rotor housing. Test results on a 65 mm (2.56 in) bump-foil thrust bearing at 100 krpm show a marked increase in load capacity with gas density, which has not previously been shown experimentally. Results also show that the load capacity of a similarly sized spiral-groove thrust bearing are relatively insensitive to pressure, and supported an order-of-magnitude less load than that observed for the bump-foil thrust bearing. These results are compared with analytical predictions, which agree reasonably with the experimental results. Predicted power loss is also presented for the bump-foil bearing; however, measured power loss was substantially higher.


Author(s):  
Franck Balducchi ◽  
Mihai Arghir ◽  
Romain Gauthier

The paper deals with the experimental analysis of the dynamic characteristics of a foil thrust bearing (FTB) designed following the specifications given by NASA in 2009. The start-up characteristics of the same foil bearing were investigated in a recently published paper. The test rig used for start-up measurements was adapted for dynamic measurements. The paper presents the test rig in detail as well as its identified dynamic models. Measurements of the dynamic characteristics of the bump foil structure were performed for static loads comprised between 30 N and 150 N while measurements for the FTB were performed at 35 krpm for 30 N, 60 N and 90 N. Excitation frequencies were comprised between 150 Hz and 750 Hz. Results showed that the dynamic stiffness of the FTB increase with excitation frequency while the equivalent damping decreases. Both stiffness and damping increase with the static load but are smaller at 35 krpm compared to 0 rpm.


2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Franck Balducchi ◽  
Mihaï Arghir ◽  
Romain Gauthier ◽  
Emelyne Renard

The paper deals with the experimental analysis of the torque and of the lift-off velocity of a foil thrust bearing. The geometric characteristics of the foil thrust bearing follow the design recently proposed by Dykas et al. (2009, “Design, Fabrication, and Performance of Foil Gas Thrust Bearings for Microturbomachinery Applications,” ASME J. Eng. Gas Turbines Power, 131(1), p. 012301-1). A dedicated test rig was developed and enables the measurement of the speed, the torque, and temperatures under the foils. The measurements underlined the importance of managing heat transfer in a foil thrust bearing. Results are presented for mild static loads ranging from 5 to 60 N and rotation speeds comprised between 20 and 35 krpm. The value of the start-up torque was validated by comparisons with results obtained with a rapid camera.


Wear ◽  
2008 ◽  
Vol 265 (7-8) ◽  
pp. 1076-1086 ◽  
Author(s):  
Christopher E. Fanning ◽  
Thierry A. Blanchet

Alloy Digest ◽  
1996 ◽  
Vol 45 (1) ◽  

Abstract Allegheny Ludlum AL276 is widely used in the most severe environments found in chemical plants and in power plant desulfurization systems. The high molybdenum level with tungsten gives excellent pitting and crevice corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, joining, and surface treatment. Filing Code: Ni-497. Producer or source: Allegheny Ludlum Corporation.


Alloy Digest ◽  
1995 ◽  
Vol 44 (3) ◽  

Abstract NICROFER 5520 Co is a nickel-chromium-cobalt-molybdenum alloy with excellent strength and creep properties up to high temperatures. Due to its balanced chemical composition the alloy shows outstanding resistance to high temperature corrosion in the form of oxidation and carburization. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ni-480. Producer or source: VDM Technologies Corporation.


Alloy Digest ◽  
1993 ◽  
Vol 42 (10) ◽  

Abstract ALTEMP HX is an austenitic nickel-base alloy designed for outstanding oxidation and strength at high temperatures. The alloy is solid-solution strengthened. Applications include uses in the aerospace, heat treatment and petrochemical markets. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, and joining. Filing Code: Ni-442. Producer or source: Allegheny Ludlum Corporation.


Alloy Digest ◽  
1993 ◽  
Vol 42 (7) ◽  

Abstract DELORO 716 PM is a nickel-base alloy recommended for handling conditions of wear, erosion, heat and corrosion when impact is also a consideration. This datasheet provides information on composition, physical properties, and hardness. It also includes information on high temperature performance and wear resistance as well as machining and joining. Filing Code: Ni-435. Producer or source: Deloro Stellite Inc.


Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  

Abstract NILO alloy 36 is a binary iron-nickel alloy having a very low and essentially constant coefficient of thermal expansion at atmospheric temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-79. Producer or source: Inco Alloys International Inc..


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