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Research Papers: Flows in Complex Systems

# Influence of Centrifugal Forces on Oil Flow in Journal Bearing of Planetary Gear

[+] Author and Article Information
Mikhail Temis

Central Institute of Aviation Motors,
Bauman Moscow State Technical University,
2, Aviamotornaya Street,
Moscow 111116, Russia
e-mail: mikhail.temis@gmail.com

Alexander Lazarev

Central Institute of Aviation Motors,
Bauman Moscow State Technical University,
2, Aviamotornaya Street,
Moscow 111116, Russia
e-mail: lytlazarev@gmail.com

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received August 20, 2016; final manuscript received August 26, 2017; published online November 3, 2017. Assoc. Editor: Olivier Coutier-Delgosha.

J. Fluids Eng 140(2), 021109 (Nov 03, 2017) (7 pages) Paper No: FE-16-1532; doi: 10.1115/1.4037982 History: Received August 20, 2016; Revised August 26, 2017

## Abstract

Mathematical model of oil flow in fluid film bearing in field of centrifugal forces is developed. Centrifugal forces for planet wheel bearing sliding surfaces and oil gap are formulated. This model is based on modification of two-dimensional Reynolds equation taking into account inertia centrifugal forces for oil film. Required modification of Reynolds equation is received from Navier–Stokes and continuity equations taking into account centrifugal forces acting on planet wheel bearing. Modified two-dimensional Reynolds equation is solved numerically using finite element discretization. Developed mathematical model, based on modified Reynolds equation, is verificated at comparison with solution of full Navier–Stokes equations system obtained in commercial software package. Results for pressure distribution in bearing with fixed axis and in planet wheel bearing are received and compared. The sufficient influence of centrifugal inertia forces in oil layer of planet wheel bearing on pressure distribution, bearing carrying force, and attitude angle is shown for specific shaft journal eccentricity ratio, eccentricity direction, and rotation velocity.

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## Figures

Fig. 1

Planetary gear: (a) structure: 1—sun wheel, H—carrier, 2—planet wheel, and 3—ring wheel and (b) accelerations on sliding surfaces of journal bearing

Fig. 2

Velocities in lubrication gap

Fig. 3

star-cd model

Fig. 4

Pressure distribution in bearing: (a) comparison of star-cd and Reynolds models for rotating and fixed carrier, (b) scheme of shaft journal displacements in bearing, and (c) contribution of pressure caused by centrifugal forces

Fig. 5

Pressure distribution on bearing for eccentricity directions 00 deg and 90 deg

Fig. 6

Pressure distribution on bearing for eccentricity directions 180 deg and 270 deg

Fig. 7

Bearing carrying force for different eccentricity directions: (a) for χ = 0.2 and (b) for different eccentricity values

Fig. 8

Attitude angle for different eccentricity directions: (a) for χ = 0.2 and (b) for different eccentricity values

Fig. 9

Bearing carrying force ratio for carrying force in bearing with fixed axis

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