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Meccanica

, 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

Abstract

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.

Keywords

Gas thrust bearing Groove Circular pad Discharge coefficient 

Nomenclature

b

critical ratio

cd

discharge coefficient of supply orifices

d

supply orifice diameter

d0

insert diameter

l

supply orifice length

h

air clearance

hg

groove depth

r

radial direction

rg

radius of supply circumference

pa

ambient absolute pressure

ps

supply absolute pressure

pc

supply orifice downstream absolute pressure

q

inlet mass flow rate per unit surface

qr

radial mass flow rate per unit circumf. length

qθ

circumf. mass flow rate per unit radial length

wg

width of the annular groove

Cs

conductance of supply port

N

number of supply orifices

R0

gas constant=287.6 m2/s2 K

S

supply orifice cross section

T0

absolute temperature in normal condition

δ

pocket depth

θ

circumferential angle

φe

pad external diameter

φi

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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