An Investigation of “Diaphragm” Type Thrust Bearings—Part II: Theory

1975 ◽  
Vol 97 (4) ◽  
pp. 577-584 ◽  
Author(s):  
A. K. Tieu
Keyword(s):  
Thermal Effects ◽  
Three Dimensional ◽  
Finite Width ◽  
Oil Film ◽  
Thrust Bearings ◽  
Temperature Boundary ◽  
Tilting Pad ◽  
Load Carrying ◽  
Theory And Experiment ◽  
Good Agreement

The three types of finite width thrust bearings, tilting pad, diaphragm tilting pad and diaphragm stepped pad, are simulated on the PDP-6 computer taking into account thermal effects on the oil film viscosity and the diaphragm deflection. The temperature boundary conditions of the three-dimensional oil film volume are obtained from the experiment described in Part I. The computed load carrying capacities of the three types of thrust bearings are compared with the experimental results, and quite good agreement between theory and experiment is obtained.

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings: Part II — Comparison Between Theory and Experiment

2006 ◽  
Author(s):  
Niels Heinrichson ◽  
Axel Fuerst ◽  
Ilmar Ferreira Santos
Keyword(s):  
Film Thickness ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Leading Edge ◽  
Operating Conditions ◽  
Oil Film ◽  
Thrust Bearings ◽  
Tilting Pad ◽  
High Pressure Injection ◽  
Theoretical Pressure

This is Part II of a two-part series of papers describing the effects of high pressure injection pockets on the operating conditions of tilting-pad thrust bearings. Measurements of the distribution of pressure and oil film thickness are presented for tilting-pad thrust bearing pads of approximately 100 cm2 surface area. Two pads are measured in a laboratory test-rig at loads of approximately 0.5, 1.5 and 4.0 MPa and velocities of up to 33 m/s. One pad has a plain surface. The other pad has a conical injection pocket at the pivot point and a leading edge taper. The measurements are compared to theoretical values obtained using a three dimensional thermoelasto-hydrodynamic (TEHD) numerical model. At low and intermediate loads the theoretical pressure distribution corresponds well to the measured values for both pads although the influence of the pocket is slightly underestimated. At high loads large discrepancies exist for the pad with an injection pocket. It is argued that this is likely to be due to the unevenness of the collar surface. The measured and theoretical values of oil film thickness compare well at low loads. At high loads discrepancies grow to up to 25 %. It is argued that this is due to the accuracy of the measurements.

A Three-Dimensional oil film Temperature Distribution in Tilting Thrust Bearings

1974 ◽  
Vol 16 (2) ◽  
pp. 121-124 ◽  
Author(s):  
A. K. Tieu
Keyword(s):  
Finite Element Method ◽  
Numerical Scheme ◽  
Three Dimensional ◽  
Finite Width ◽  
The Finite Element Method ◽  
Oil Film ◽  
Thrust Bearings ◽  
Pressure Distributions ◽  
Temperature And Pressure ◽  
Thrust Pad

The oil film temperature and pressure distributions of the finite width Michell tilting thrust pad are determined from a numerical scheme based on the finite element method. These computed results correlate very well with those obtained from the experiment.

A Numerical Simulation of Finite-Width Thrust Bearings, Taking into Account Viscosity Variation with Temperature and Pressure

1975 ◽  
Vol 17 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. K. Tieu
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Three Dimensional ◽  
Finite Width ◽  
Element Analysis ◽  
Factors Affecting ◽  
Oil Film ◽  
Thrust Bearings ◽  
Carry Over ◽  
Thrust Pad

A variational principle for a thin-film incompressible flow with viscous dissipation has already been formulated as the basis of a finite-element analysis and applied to solve the oil-film energy equation for the case of infinitely wide thrust bearings (1)†. Here, the finite-element method is extended to a three-dimensional oil film, the pressure and temperature distributions of which agree very well with those obtained from other theoretical and experimental work. Allowance for various factors affecting thrust-pad performance, such as hot oil carry-over, rotor surface temperature and pad radial tilting, in the non-isoviscous bearing analysis has been shown to improve the agreement between numerical simulation and experiment.

Computational Fluid Dynamics Thermohydrodynamic Analysis of Three-Dimensional Sector-Pad Thrust Bearings With Rectangular Dimples

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
C. I. Papadopoulos ◽  
L. Kaiktsis ◽  
M. Fillon
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Carrying Capacity ◽  
Thermal Effects ◽  
Operating Conditions ◽  
Load Carrying Capacity ◽  
Performance Indices ◽  
Thrust Bearings ◽  
Load Carrying ◽  
Texture Design

The paper presents a detailed computational study of flow patterns and performance indices in a dimpled parallel thrust bearing. The bearing consists of eight pads; the stator surface of each pad is partially textured with rectangular dimples, aiming at maximizing the load carrying capacity. The bearing tribological performance is characterized by means of computational fluid dynamics (CFD) simulations, based on the numerical solution of the Navier–Stokes and energy equations for incompressible flow. Realistic boundary conditions are implemented. The effects of operating conditions and texture design are studied for the case of isothermal flow. First, for a reference texture pattern, the effects of varying operating conditions, in particular minimum film thickness (thrust load), rotational speed and feeding oil pressure are investigated. Next, the effects of varying texture geometry characteristics, in particular texture zone circumferential/radial extent, dimple depth, and texture density on the bearing performance indices (load carrying capacity, friction torque, and friction coefficient) are studied, for a representative operating point. For the reference texture design, the effects of varying operating conditions are further investigated, by also taking into account thermal effects. In particular, adiabatic conditions and conjugate heat transfer at the bearing pad are considered. The results of the present study indicate that parallel thrust bearings textured by proper rectangular dimples are characterized by substantial load carrying capacity levels. Thermal effects may significantly reduce load capacity, especially in the range of high speeds and high loads. Based on the present results, favorable texture designs can be assessed.

A Three-Dimensional Analysis of Thermohydrodynamic Performance of Sector-Shaped, Tilting-Pad Thrust Bearings

1983 ◽  
Vol 105 (3) ◽  
pp. 406-412 ◽  
Author(s):  
Kyung Woong Kim ◽  
Masato Tanaka ◽  
Yukio Hori
Keyword(s):  
Dimensional Analysis ◽  
Environmental Conditions ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Thrust Bearings ◽  
Tilting Pad ◽  
Dimensional Variation ◽  
Lubricant Viscosity

The thermohydrodynamic performance of the bearing is analyzed, taking into account the three-dimensional variation of lubricant viscosity and density. The effect of pivot position and operating and environmental conditions on the performance is studied. The present analysis is compared with the isoviscous or the two-dimensional analysis, and is found to predict the bearing performance more accurately.

scholarly journals Cooled Pads for Tilting-Pad Journal Bearings

Lubricants ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 92
Author(s):  
Steven Chatterton ◽  
Paolo Pennacchi ◽  
Andrea Vania ◽  
Phuoc Vinh Dang
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Journal Bearings ◽  
Maximum Temperature ◽  
Inlet Temperature ◽  
Oil Film ◽  
External Cooling ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearings

Tilting-pad journal bearings (TPJBs) are widely installed in rotating machines owing to their high stability, but some drawbacks can be noted, such as higher cost with respect to cylindrical journal bearings and thermal issues. High temperatures in the pads correspond to low oil-film thicknesses and large thermal deformations in the pads. Therefore, the restriction of the maximum temperature of the bearing is a key aspect for oil-film bearings. The temperature reduction is generally obtained by adopting higher oil inlet flowrates or suitable oil nozzles. In this paper, the idea of using cooled pads with internal channels in which an external cooling fluid is circulated will be applied to a TPJB for the first time. The three-dimensional TEHD model of the TPJB, equipped with a cooled pad, will be introduced, and the results of the numerical simulations will be discussed. Several analyses have been performed in order to investigate the influence of cooling conditions, such as the type, flowrate, inlet temperature and number of cooled pads. Two types of pad geometry with different cross-sections of the cooling circuit, namely, circular and six-square multi-channel sections, have been compared to the reference bearing with solid pads. Simple experimental tests were performed by means of a test rig equipped with a cooled pad bearing obtained with the additive manufacturing process, thus showing the effectiveness of the solution and the agreement with the predictions.

Improvement and Analysis for a Gaseous Cavitation Model Applied in a Tilting-Pad Journal Bearing

2019 ◽  
Author(s):  
Aoshuang Ding ◽  
Xuesong Li ◽  
Yuhong Li
Keyword(s):  
Journal Bearing ◽  
Three Dimensional ◽  
Cavitation Model ◽  
Local Pressure ◽  
Cavitation Process ◽  
Air Volume ◽  
Tilting Pad ◽  
Sst Model ◽  
Tilting Pad Journal Bearing ◽  
Good Agreement

Abstract Considering the gaseous cavitation rate is influenced by local pressure, a transient gaseous cavitation model is developed from an equilibrium gaseous cavitation model in consideration of transient gaseous cavitation theories and the Bunsen solubility. With the shear stress transport (SST) model with low-Re correction and air backflow from the bearing outlets, the transient gaseous cavitation model is applied to the three-dimensional simulations of an entire tilting-pad journal bearing at 3000 rpm speed and under 180 kN load. The simulated bearing pressure and load are in good agreement with the experimental data, indicating that the transient gaseous cavitation model performs well in the bearing simulations. Based on the comparisons of the simulated air and dissolved air distributions between the transient and equilibrium gaseous cavitation models, the simulated cavitation process of the transient gaseous cavitation is proved to be not in equilibrium and mass transfer occur between the backflow air and oil. The purpose of building the transient gaseous cavitation model is thus met. Analyses of the air distributions indicate that high cavitation rates and low dissolution rates makes air volume a major part of the total air volume and close to the physical gaseous cavitation process.

Geometry Optimization of Textured Three-Dimensional Micro- Thrust Bearings

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
C. I. Papadopoulos ◽  
E. E. Efstathiou ◽  
P. G. Nikolakopoulos ◽  
L. Kaiktsis
Keyword(s):  
Carrying Capacity ◽  
Stokes Equations ◽  
Load Capacity ◽  
Three Dimensional ◽  
Load Carrying Capacity ◽  
Thrust Bearings ◽  
Micro Channels ◽  
Wide Range ◽  
Load Carrying ◽  
Bearing Load

This paper presents an optimization study of the geometry of three-dimensional micro-thrust bearings in a wide range of convergence ratios. The optimization goal is the maximization of the bearing load carrying capacity. The bearings are modeled as micro-channels, consisting of a smooth moving wall (rotor), and a stationary wall (stator) with partial periodic rectangular texturing. The flow field is calculated from the numerical solution of the Navier-Stokes equations for incompressible isothermal flow; processing of the results yields the bearing load capacity and friction coefficient. The geometry of the textured channel is defined parametrically for several width-to-length ratios. Optimal texturing geometries are obtained by utilizing an optimization tool based on genetic algorithms, which is coupled to the CFD code. Here, the design variables define the bearing geometry and convergence ratio. To minimize the computational cost, a multi-objective approach is proposed, consisting in the simultaneous maximization of the load carrying capacity and minimization of the bearing convergence ratio. The optimal solutions, identified based on the concept of Pareto dominance, are equivalent to those of single-objective optimization problems for different convergence ratio values. The present results demonstrate that the characteristics of the optimal texturing patterns depend strongly on both the convergence ratio and the width-to-length ratio. Further, the optimal load carrying capacity increases at increasing convergence ratio, up to an optimal value, identified by the optimization procedure. Finally, proper surface texturing provides substantial load carrying capacity even for parallel or slightly diverging bearings. Based on the present results, we propose simple formulas for the design of textured micro-thrust bearings.

Sensitivity Studies for the Shallow-Pocket Geometry of a Hydrostatic Thrust Bearing

2003 ◽  
Author(s):  
Robert E. Johnson ◽  
Noah D. Manring
Keyword(s):  
Closed Form ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Closed Form Expression ◽  
Pocket Depth ◽  
Thrust Bearings ◽  
Heavy Equipment ◽  
Load Carrying ◽  
Sensitivity Studies ◽  
Basic Features

Hydrostatic thrust bearings have been the object of considerable research for many years. The attention that these bearings have received is primarily due to the important role they play in the design and operation of heavy equipment. In this role, the hydrostatic thrust bearing is often considered to be the “Achilles heel” of the total machine system as failures result in catastrophic difficulties and expensive repairs. The objectives of this research are to examine the nuances of designing a hydorstatic thrust bearing using a shallow pocket as opposed to the more traditional deep pocket design. By using a two-dimensional model for this geometry, the basic features of the shallow pocket design are extracted in closed-form and behaviors that would be expected in the three-dimensional setting are identified. In this research, a single dimensionless parameter is used to describe the influence of the bearing speed under laminar flow conditions. The principal results of this research are closed-form expression that describe the load carrying capcity of the bearing, the tilting moment exerted on the bearing by a skewed pressure distribution, and the volumetric leakage of the bearing. Sensitivity studies are conducted using these results and the influence of small perturbations of the pocket depth are identified for bearings with different pocket widths. These results are discussed and conclusions are itemized in the final section of the paper.

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