, Volume 46, Issue 3, pp 547–555 | Cite as

Comparison between grooved and plane aerostatic thrust bearings: static performance

  • Guido Belforte
  • Federico Colombo
  • Terenziano Raparelli
  • Andrea Trivella
  • Vladimir Viktorov
Asperity Contacts & Lubrication Aspects


The demand of air bearings is increasing for those applications that require precision linear movements or high-speed rotations. In particular in this paper air pads for air motion technology are studied. The paper analyses the effect of a circumferential groove machined on the pad surface on pressure distribution, air flow consumption and stiffness. Two geometries are investigated and compared: one with three supply orifices and the other with a circumferential groove as well. The static characteristics of the pads are experimentally determined with also the pressure distributions under the pads along the radial and circumferential directions. The experimental pressure distributions are compared with the simulated ones, obtained with a numerical program at the purpose developed. The numerical model considers a general formulation of the supply holes discharge coefficient that can be used also in presence of a circumferential groove.


Gas thrust bearing Groove Circular pad Discharge coefficient 



critical ratio


discharge coefficient of supply orifices


supply orifice diameter


insert diameter


supply orifice length


air clearance


groove depth


radial direction


radius of supply circumference


ambient absolute pressure


supply absolute pressure


supply orifice downstream absolute pressure


inlet mass flow rate per unit surface


radial mass flow rate per unit circumf. length


circumf. mass flow rate per unit radial length


width of the annular groove


conductance of supply port


number of supply orifices


gas constant=287.6 m2/s2 K


supply orifice cross section


absolute temperature in normal condition


pocket depth


circumferential angle


pad external diameter


pad internal diameter


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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Guido Belforte
    • 1
  • Federico Colombo
    • 1
  • Terenziano Raparelli
    • 1
  • Andrea Trivella
    • 1
  • Vladimir Viktorov
    • 1
  1. 1.Department of MechanicsPolitecnico di TorinoTurinItaly

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