Behaviour of porous aerostatic bearings with various restrictor permeabilities

Maria Hübner*, Mikael Miettinen, Valtteri Vainio, Christian Cierpka, René Theska, Raine Viitala

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

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Abstract

Aerostatic bearings are externally pressurized gas lubricated bearings. Aerostatic bearings are used in high speed and precision motion applications due to low friction and high accuracy. They use a restrictor to limit the flow of the gas into the bearing gap. The presence of the restrictor increases the stability of the bearing against self-excited vibrations. This study focuses on porous graphite restrictors and the effect of permeability on the behaviour of the bearing. The bearings were studied both experimentally and with a simulation model. Flat bearing pads with 37 mm diameter and different restrictor bulk permeability were manufactured and tested. Experimental measurements were conducted on a test setup allowing loading of the bearing against a ground steel plate. The load was supplied with a series of weights. The air gap was measured with a linear length gauge, measuring the displacement of the air bearing. The pressure was controlled with a regulator and the flow rate into the bearing was measured. In order to build an accurate simulation model, the permeability of the used material was calculated from the measured short circuit flow through each 4.5 mm thick sample. The flow in the porous material and in the restrictive layer follows Darcy’s law, the flow in the air gap is described by the Navier-Stokes-equation. The simulation model was validated with experimental results. Measurement and simulation results include the air gap height, load and flow rate at a supply pressure of 0.4 MPa. According to previous research and preliminary results the surface restrictor layer has increased the resistance of the bearing to self-excited air-hammer vibration, leading to a higher load capacity.

Original languageEnglish
Title of host publicationProceedings of the 21st International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2021
EditorsR. K. Leach, C. Nisbet, D. Phillips
Publishereuspen
Pages115-118
Number of pages4
ISBN (Electronic)9780995775190
Publication statusPublished - 2021
MoE publication typeA4 Article in a conference publication
EventInternational Conference of the European Society for Precision Engineering and Nanotechnology - Virtual, Online
Duration: 7 Jun 202110 Jun 2021
Conference number: 21

Publication series

NameProceedings of the 21st International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2021

Conference

ConferenceInternational Conference of the European Society for Precision Engineering and Nanotechnology
Abbreviated titleEUSPEN
CityVirtual, Online
Period07/06/202110/06/2021

Keywords

  • Aerostatic bearing
  • Porous restrictor
  • Restrictive layer

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