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Thermal performance measurement of a bump type gas foil bearing floating on a hollow shaft for increasing rotating speed and static load / Tae Ho Kim in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 134 N° 2 (Février 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 2 (Février 2012) . - 05 p. Titre : Thermal performance measurement of a bump type gas foil bearing floating on a hollow shaft for increasing rotating speed and static load Type de document : texte imprimé Auteurs : Tae Ho Kim, Auteur ; Jin Woo Song, Auteur ; Yong-Bok Lee, Auteur ; Kyuho Sim, Auteur Année de publication : 2012 Article en page(s) : 05 p. Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Machine  bearings  Motor  drives  Strain  gauges  Temperature  measurement  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Identifying thermal characteristics of gas foil bearings (GFBs) provides an insight for successful implementation into high speed oil-free turbomachinery. The paper presents temperature measurements of a bump type GFB floating on a hollow shaft for various operating conditions. Two angular ball bearings support the hollow shaft at one end (right), and the other end (left) is free. Test GFB has the outer diameter of 100 mm and the axial length of 45 mm, and the hollow shaft has the outer and inner diameters of 60 mm and 40 mm, respectively. An electric motor drives the hollow shaft using a spline coupling connection. A mechanical loading device provides static loads on test GFB upward via a metal wire, and a strain gauge type load cell placed in the middle of the wire indicates the applied loads. During experiments for shaft speeds of 5 krpm, 10 krpm, and 15 krpm and with static loads of 58.9 N (6 kgf), 78.5 N (8 kgf), and 98.1 N (10 kgf), twelve thermocouples measure the outer surface temperatures of test GFB at four angular locations of 45 deg, 135 deg, 215 deg, and 315 deg, with an origin at the top foil free end, and three axial locations of bearing centerline and both side edges at each angle. Two infrared thermometers measure the outer surface temperature of the hollow shaft at free and supported ends close to test GFB. Test results show that GFB temperatures increase as the shaft speed increases and as the static load increases, with higher temperatures in the loaded zone (135 deg and 215 deg) than those in the unloaded zone (45 deg and 315 deg). In general, the recorded temperatures are highest at 225 deg where a highest hydrodynamic pressure is expected to build up. Measured temperatures at the bearing centerline are higher than those at the side edges, as expected. In addition, large thermal gradients are recorded in the hollow shaft along the axial direction with higher temperatures at the supported end. The axial thermal gradient of the shaft is thought to cause higher temperatures at the bearing right edge facing the ball bearing support than those at the left edge. The paper presents test data along with detailed test GFB/shaft geometries and material properties. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000002 [...] [article] Thermal performance measurement of a bump type gas foil bearing floating on a hollow shaft for increasing rotating speed and static load [texte imprimé] / Tae Ho Kim, Auteur ; Jin Woo Song, Auteur ; Yong-Bok Lee, Auteur ; Kyuho Sim, Auteur . - 2012 . - 05 p. Génie mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 2 (Février 2012) . - 05 p. Mots-clés : Machine  bearings  Motor  drives  Strain  gauges  Temperature  measurement  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Identifying thermal characteristics of gas foil bearings (GFBs) provides an insight for successful implementation into high speed oil-free turbomachinery. The paper presents temperature measurements of a bump type GFB floating on a hollow shaft for various operating conditions. Two angular ball bearings support the hollow shaft at one end (right), and the other end (left) is free. Test GFB has the outer diameter of 100 mm and the axial length of 45 mm, and the hollow shaft has the outer and inner diameters of 60 mm and 40 mm, respectively. An electric motor drives the hollow shaft using a spline coupling connection. A mechanical loading device provides static loads on test GFB upward via a metal wire, and a strain gauge type load cell placed in the middle of the wire indicates the applied loads. During experiments for shaft speeds of 5 krpm, 10 krpm, and 15 krpm and with static loads of 58.9 N (6 kgf), 78.5 N (8 kgf), and 98.1 N (10 kgf), twelve thermocouples measure the outer surface temperatures of test GFB at four angular locations of 45 deg, 135 deg, 215 deg, and 315 deg, with an origin at the top foil free end, and three axial locations of bearing centerline and both side edges at each angle. Two infrared thermometers measure the outer surface temperature of the hollow shaft at free and supported ends close to test GFB. Test results show that GFB temperatures increase as the shaft speed increases and as the static load increases, with higher temperatures in the loaded zone (135 deg and 215 deg) than those in the unloaded zone (45 deg and 315 deg). In general, the recorded temperatures are highest at 225 deg where a highest hydrodynamic pressure is expected to build up. Measured temperatures at the bearing centerline are higher than those at the side edges, as expected. In addition, large thermal gradients are recorded in the hollow shaft along the axial direction with higher temperatures at the supported end. The axial thermal gradient of the shaft is thought to cause higher temperatures at the bearing right edge facing the ball bearing support than those at the left edge. The paper presents test data along with detailed test GFB/shaft geometries and material properties. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000002 [...]