Analysis of Hydrodynamic Journal Bearings Having Non-Newtonian Lubricants (Prandtl Model) by a Finite Element Method

1981 ◽  
Vol 23 (2) ◽  
pp. 63-68 ◽  
Author(s):  
S. P. Tayal ◽  
R. Sinhasan ◽  
D. V. Singh
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Journal Bearings ◽  
Newtonian Fluids ◽  
Finite Width ◽  
Nonlinear Behaviour ◽  
Prandtl Model ◽  
Element Method

Additives are used to improve the performance of commercial lubricants. These lubricants behave like non-Newtonian fluids (shear thinning or shear thickening). The effect of the nonlinear behaviour on the performance characteristics of finite width journal bearings is investigated using the Prandtl model. The finite element method, using Galerkin's technique, has been used to solve the Navier-Stokes equations in cylindrical coordinates, representing the flow-field in the clearance space of a bearing using Newtonian fluids, and the non-Newtonian effect is introduced by modifying the viscosity term for the model in each iteration. The results applicable to shear-thinning (pseudoplastic) and shear-thickening (dilatant) lubricants are compared with the established results for Newtonian lubricants.

An Extrapolation Method to Compute Far-Field Pressures From Near-Field Pressures Obtained by Finite Element Method

1995 ◽  
Author(s):  
Jamal Assaad ◽  
Christian Bruneel ◽  
Jean-Michel Rouvaen ◽  
Régis Bossut
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Near Field ◽  
Radiation Condition ◽  
Directivity Pattern ◽  
Extrapolation Method ◽  
External Boundary ◽  
Finite Width ◽  
Far Field ◽  
Element Method

Abstract The finite element method is widely used for the modeling of piezoelectric transducers. With respect to the radiation loading, the fluid is meshed and terminated by an external nonreflecting surface. This reflecting surface can be made up with dipolar damping elements that absorb approximately the outgoing acoustic wave. In fact, with dipolar dampers the fluid mesh can be quite limited. This method can provides a direct computation of the near-field pressure inside the selected external boundary. This paper describes an original extrapolation method to compute far-field pressures from near-field pressures in the two-dimensional (2-D) case. In fact, using the 2-D Helmholtz equation and its solution obeying the Sommerfeld radiation condition, the far-field directivity pattern can be expressed in terms of the near-field directivity pattern. These developments are valid for any radiation problem in 2D. One test example is described which consists of a finite width planar source mounted in a rigid or a soft baffle. Experimental results concerning the far-field directivity pattern of lithium niobate bars (Y-cut) are also presented.

Analysis of Aerodynamic Journal Bearings With Small Number of Herringbone Grooves by Finite Element Method

1994 ◽  
Vol 116 (4) ◽  
pp. 698-704 ◽  
Author(s):  
D. Bonneau ◽  
J. Absi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Study ◽  
Load Capacity ◽  
Journal Bearings ◽  
The Finite Element Method ◽  
Bearing Number ◽  
Comparison Of The Results ◽  
Herringbone Grooves ◽  
Element Method

A numerical study of gas herringbone grooved journal bearings is presented for small number of grooves. The compressible Reynolds equation is solved by use of the Finite Element Method. The nonlinearity of the discretized equations is treated with the Newton-Raphson procedure. A comparison of the results for a smooth bearing with previously published results is made and the domain of validity of the Narrow Groove Theory is analyzed. Load capacity, attitude angle, and stiffness coefficients are given for various configurations: groove angle and thickness of grooves, bearing number, and that for both smooth and grooved member rotating.

scholarly journals Tribology of High Speed Aerodynamic Foil Journal Bearings

1997 ◽  
Author(s):  
D. Sudheer Kumar Reddy ◽  
S. Swarnamani ◽  
B. S. Prabhu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Speed ◽  
Perturbation Technique ◽  
Journal Bearings ◽  
Rotating Shaft ◽  
Aerodynamic Pressure ◽  
Foil Bearing ◽  
Bearing Number ◽  
Element Method

Foil journal bearings come under the category of air lubricated journal bearings where the lubricant is atmospheric air. In this type of bearings the pressure developed is due to the aerodynamic wedge developed between the rotating shaft and the foil bearing surface. This paper is concerned with the analysis of the bending dominated type foil bearing, in which the compliance is effected mainly through the bending of foils. The nonlinear Reynolds equation has been used for the aerodynamic pressure solution. Effect of elastohydrodynamics on foil journal bearing has been studied. The problem has been formulated using incremental finite element method. Two types of bending dominated foil bearings have been considered for analysis, namely straight foil type and curved foil type bearings. The equations for the dynamic coefficients were obtained by a perturbation technique and the results were computed using the finite element method. The effect of bearing compliance and the bearing number on performance parameters has been studied, the results were compared with the available literature.

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