Performance of textured spherical thrust hybrid bearing operating with shear thinning and piezoviscous lubricants

2021 ◽  
pp. 135065012110313
Author(s):  
Nitin Agrawal ◽  
Satish C Sharma
Keyword(s):  
Power Loss ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Strong Dependence ◽  
Shear Thinning ◽  
Flow Equation ◽  
Textured Surfaces ◽  
Bearing Surface ◽  
Fluid Film Bearings ◽  
Hybrid Bearing

Improving the lubricating performance of tribo-pairs using engineering textured surfaces has been the main focus of tribology research in recent years. The use of a suitably designed micro-texture on the bearing surface may have a beneficial effect on the performance of fluid film bearings. In the present paper, a mathematical model of a hybrid spherical thrust bearing is developed considering the effect of shear thinning and piezoviscous behaviour of a lubricant. The modified Reynolds equation for a hybrid spherical thrust bearing configuration together with a restrictor flow equation for a capillary restrictor is solved using a finite-element method. In this work, the effect of various micro-textures shapes (spherical, circular, conical and square) and non-Newtonian lubricant behaviour having shear thinning and piezoviscous effects are analysed. The numerically simulated result shows a strong dependence on the combined effect of shear thinning and piezoviscous lubricant behaviour and a chosen geometric shape of a texture. The frictional power loss is seen to reduce nearly by 24.05%, and the stiffness gets enhanced by 11.08%.

Influence of micro-groove attributes on frictional power loss and load-carrying capacity of hybrid thrust bearing

2019 ◽  
Vol 72 (5) ◽  
pp. 589-598 ◽  
Author(s):  
Vivek Kumar ◽  
Satish C. Sharma ◽  
Kuldeep Narwat
Keyword(s):  
Reynolds Equation ◽  
Thrust Bearing ◽  
Surface Texturing ◽  
Fluid Film ◽  
Element Formulation ◽  
Textured Surfaces ◽  
Content Type ◽  
Cavitation Phenomenon ◽  
Fluid Film Bearings ◽  
Load Carrying

Purpose Micro-surface texturing is emerging as a possible way to enhance the tribological performance of hydrodynamic fluid film bearings. In view of this, numerical simulations are carried out to examine the influence of surface texture on performance of hybrid thrust bearing system. This paper aims to determine optimum attributes of micro-grooves for thrust bearing operating in hybrid mode. Design/methodology/approach An iterative source code based on finite element formulation of Reynolds equation has been developed to numerically simulate flow of lubricant through the bearing. Mass-conserving algorithm based on Jakobsson–Floberg–Olsson (JFO) condition has been used to numerically capture cavitation phenomenon in the bearing. Gauss Siedel method has been used to obtain steady state performance parameters of the bearings. Findings A parametric study has been performed to improve the load supporting capacity of the bearing by optimizing micro-groove attributes and configuration. It is noticed that use of full-section micro-groove is beneficial in improving the efficiency of bearing by enhancing the fluid film reaction and reducing the film frictional power losses. Originality/value This study is helpful in examining the usefulness of micro-groove textured surfaces in hybrid thrust bearing applications.

Effect of Speed on the Performance Characteristics of Non-Recessed Worn Hybrid Conical Journal Bearing for Different Semi Cone Angles

2018 ◽  
Author(s):  
Vikas M. Phalle ◽  
Sanjay R. Pawar ◽  
Sangram S. Patil
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Flow Equation ◽  
Performance Characteristics ◽  
Appreciable Change ◽  
Spherical Coordinate ◽  
Speed Parameter ◽  
Conical Bearing ◽  
Hybrid Bearing ◽  
Flow Valve

The conical fluid film hybrid journal bearing may be developed as a modification to overcome the adverse effects of cylindrical journal bearing configuration. Hybrid bearing also have a capability to take advantage of simultaneous hydrodynamic and hydrostatic action. This paper aims to study analytically the performance characteristics of a non-recessed, worn hybrid conical journal bearing compensated with constant flow valve as restrictor. The Reynolds equation for conical bearing is developed in spherical coordinate system for governing the flow of iso-viscous incompressible fluid in the clearance space of conical journal and bearing and it is solved by finite element method together with restrictor flow equation. Numerically simulated results indicate that appreciable change in the performance characteristics of worn hybrid conical journal bearing with change in speed parameter and they are expected to be quite useful for the bearing designer.

Thermohydrodynamic Lubrication Analysis of Slider Bearings With Steps on Bearing Surface

2009 ◽  
Author(s):  
Hideki Ogata
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Fluid Velocity ◽  
Differential Method ◽  
Fluid Film ◽  
Bearing Surface ◽  
Fluid Film Bearings ◽  
Temperature Distributions ◽  
Finite Differential Method ◽  
Good Agreement

This study focuses on the thermohydrodynamic lubrication analysis of fluid film bearings with step on the surface such as a Rayleigh step bearing. In general, the Reynolds equation does not satisfy the continuity of the fluid velocity components at steps. This discontinuity results in the difficulty to solve the energy equation for the lubricants, because the energy equation needs the velocity components explicitly. The author has solved this problem by introducing the equivalent clearance height and the equivalent gradient of clearance height at steps. These parameters remove the discontinuity of velocity components and the energy equation as well, so that one can solve these equations on all of the bearing surfaces including the step region by finite differential method (FDM). The numerical results of pressure and temperature distributions by the proposed method for a Rayleigh step bearing were compared with the results obtained by a commercial CFD package. These results showed good agreement with each other. This method is extended to 2D unequal grid problems.

scholarly journals Influence of magnetorheological lubricant behavior on the performance annular recessed orifice compensated non-textured/textured thrust pad bearing

2021 ◽  
pp. 135065012110483
Author(s):  
Narendra Kumar ◽  
Satish C Sharma
Keyword(s):  
Carrying Capacity ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Flow Behavior ◽  
Pumping Power ◽  
Bingham Model ◽  
Thrust Bearings ◽  
Fluid Film Bearings ◽  
Thrust Pad ◽  
Bearing System

Fluid film bearings operated with smart lubricants have been successfully used to enhance the lubricating performance. This article proposes a computational model to analyze the influence of magnetorheological lubricant on the performance of an annular recessed hybrid thrust bearing system. The governing modified Reynolds equation for circular thrust pad orifice compensated bearing is solved by finite element method. Further, for simulating the flow behavior of magnetorheological lubricant, a constitutive relation for the Bingham model Dave equation, has been used. The numerical results reveal that using magnetorheological lubricant improves the loading carrying capacity and damping coefficient of both annular and circular recess hybrid thrust bearings. Additionally, bearing lubricated with magnetorheological lubricant requires a lesser quantity of flow and hence less pumping power.

scholarly journals Influence of Wall Porosity and Surfaces Roughness on the Steady Performance of an Externally Pressurized Hydrostatic Conical Bearing Lubricated by a Rabinowitsch Fluid

2017 ◽  
Vol 22 (3) ◽  
pp. 717-737 ◽  
Author(s):  
A. Walicka ◽  
E. Walicki ◽  
P. Jurczak ◽  
J. Falicki
Keyword(s):  
Pressure Distribution ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Hydrodynamic Lubrication ◽  
Equations Of Motion ◽  
Load Carrying Capacity ◽  
Bearing Surface ◽  
Load Carrying ◽  
Conical Bearing

AbstractIn the paper, the influence of both the bearing surfaces roughness as well as porosity of one bearing surface on the pressure distribution and load-carrying capacity of a curvilinear, externally pressurized, thrust bearing is discussed. The equations of motion of a pseudo-plastic Rabinowitsch fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and in a porous layer using the Morgan-Cameron approximation and Christensen theory of hydrodynamic lubrication with rough bearing surfaces the modified Reynolds equation is obtained. The analytical solution is presented; as a result one obtains the formulae expressing the pressure distribution and load-carrying capacity. Thrust radial and conical bearings, externally pressurized, are considered as numerical examples.

Load Capacity of a Grooved Circular Step Thrust Bearing

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
M. Zakir Hossain ◽  
M. Mahbubur Razzaque
Keyword(s):  
Inclination Angle ◽  
Power Loss ◽  
Parametric Analysis ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Groove Depth ◽  
Step Height ◽  
Bearing Surface ◽  
Pumping Power ◽  
Minimum Film Thickness

A parametric analysis based on narrow groove theory (NGT) has been presented for estimating the load capacity of a grooved circular step thrust bearing. Three types of grooving arrangements of the bearing surface, namely, (a) both the step and the recess are grooved, (b) only the step is grooved, and (c) only the recess is grooved, are considered. It is found that grooving in the step provides the most significant enhancement on the load capacity. The load capacity and the pumping power loss are affected by the step location, step height, and inertia. There is no benefit of making step location smaller than 0.6 that corresponds to the minimum power loss due to pumping. At a very large value of step location, say 0.85, the load capacity drops drastically. To take advantage of inertia as well as grooving, the dimensionless step location should be 0.6 ∼ 0.85 and the dimensionless step height should be less than 5. The load capacity also depends on groove geometry parameters such as groove inclination, groove depth, and fraction of area grooved. The groove inclination angle has been found to be the most important parameter that determines the increase or decrease in load capacity. For the most enhancement of load capacity, the inclination angle should be 135 deg with the direction of rotation, the groove depth should be at least twice the minimum film thickness, and the fraction of the step surface area grooved should be around 0.5.

scholarly journals Run-Up Simulation of a Semi-Floating Ring Supported Turbocharger Rotor Considering Thrust Bearing and Mass-Conserving Cavitation

Lubricants ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 44
Author(s):  
Christian Ziese ◽  
Cornelius Irmscher ◽  
Steffen Nitzschke ◽  
Christian Daniel ◽  
Elmar Woschke
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Reliable Prediction ◽  
Two Phase ◽  
Hydrodynamic Bearings ◽  
Thrust Bearings ◽  
Run Up ◽  
The Impact

The vibration behaviour of turbocharger rotors is influenced by the acting loads as well as by the type and arrangement of the hydrodynamic bearings and their operating condition. Due to the highly non-linear bearing behaviour, lubricant film-induced excitations can occur, which lead to sub-synchronous rotor vibrations. A significant impact on the oscillation behaviour is attributed to the pressure distribution in the hydrodynamic bearings, which is influenced by the thermo-hydrodynamic conditions and the occurrence of outgassing processes. This contribution investigates the vibration behaviour of a floating ring supported turbocharger rotor. For detailed modelling of the bearings, the Reynolds equation with mass-conserving cavitation, the three-dimensional energy equation and the heat conduction equation are solved. To examine the impact of outgassing processes and thrust bearing on the occurrence of sub-synchronous rotor vibrations separately, a variation of the bearing model is made. This includes run-up simulations considering or neglecting thrust bearings and two-phase flow in the lubrication gap. It is shown that, for a reliable prediction of sub-synchronous vibrations, both the modelling of outgassing processes in hydrodynamic bearings and the consideration of thrust bearing are necessary.

Characteristics evaluation of gas film in the aerostatic thrust bearing within rarefied effect

2016 ◽  
Vol 231 (2) ◽  
pp. 149-157 ◽  
Author(s):  
Dongju Chen ◽  
Shuai Zhou ◽  
Jihong Han ◽  
Jinwei Fan ◽  
Qiang Cheng
Keyword(s):  
Machine Tool ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Film Flow ◽  
Machining Accuracy ◽  
Aerostatic Bearing ◽  
Supply Pressure ◽  
Slip Regime ◽  
Key Factor ◽  
Gas Supply

The characteristic of gas film is a key factor in the performance of the aerostatic bearing. Because the gas film flow is in the slip regime, influence of the rarefied effect is significant. The modified Reynolds equation suitable for compressible gas in the rarefied effect is deduced through introducing the flow factor in the rarefied effect to the Reynolds equation. Pressure distribution, capacity, and stiffness of the gas film under the rarefied effect are analyzed. With the increase of gas pressure, the gas film capacity and stiffness of bearing would also increase. However, the greater the gas supply pressure, the more intense the gas film vibration, so it was important to select a reasonable gas supply pressure for achieving the optimal gas film characteristic. Finally, the gas rarefied effect is verified by the experiment indirectly, which agreed well with the analytical results and provided a theoretical guidance for the machining accuracy of the machine tool.

Stresses in Oil Lubricated Bearings

1969 ◽  
Vol 184 (1) ◽  
pp. 69-82 ◽  
Author(s):  
S. M. Ibrahim ◽  
H. Mccallion
Keyword(s):  
Thrust Bearing ◽  
Journal Bearing ◽  
Fluid Pressure ◽  
Temperature Gradients ◽  
Rigid Surface ◽  
Pressure Loading ◽  
Bearing Surface ◽  
Bearing Ring ◽  
Difference Analogue ◽  
Differential Thermal Expansion

Stresses in a bimetal strip of white metal bonded to steel, to simulate a journal bearing shell or a thrust bearing ring, have been calculated for various loading conditions. The stresses arose from: fluid pressure loading on the bearing surface whilst the back was supported on a complete rigid surface; locating and holding forces, e.g. compression due to nipping-up the bearing; elastic deformation of the bearing housing; differential thermal expansion and temperature gradients, and incomplete support of the bearing shell when subjected to fluid pressure on its bearing surface. Points at which fatigue damage is likely to originate are apparent. The stresses were calculated numerically from displacements which were found, by an iterative method, to satisfy a finite difference analogue of the governing differential equations.

Static Characteristics of Gas Foil Thrust Bearing Based on Gas Rarefaction Model

2015 ◽  
Author(s):  
Jiajia Yan ◽  
Guanghui Zhang ◽  
Zhansheng Liu ◽  
Fan Yang
Keyword(s):  
Film Thickness ◽  
Optimization Design ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Rarefied Gas ◽  
Load Capacity ◽  
Structural Parameters ◽  
Lubricating Film ◽  
Lift Off ◽  
Foil Thrust Bearing

A modified Reynolds equation for bump type gas foil thrust bearing was established with consideration of the gas rarefaction coefficient. Under rarefied gas lubrication, the Knudsen number which was affected by the film thickness and pressure was introduced to the Reynolds equation. The coupled modified Reynolds and lubricating film thickness equations were solved using Newton-Raphson Iterative Method and Finite Difference Method. By calculating the load capacity for increasing rotor speeds, the lift-off speed under certain static load was obtained. Parametric studies for a series of structural parameters and assembled clearances were carried out for bearing optimization design. The results indicate that with gas rarefaction effect, the axial load capacity would be decreased, and the lift-off speed would be improved. The rarefied gas has a more remarkable impact under a lower rotating speed and a smaller foil compliance coefficient. When the assembled clearance of the thrust bearing rotor system lies in a small value, the lift-off speed increases dramatically as the assembled clearance decreases further. Therefore, the axial clearance should be controlled carefully in assembling the foil thrust bearing. It’s worth noting that the linear uniform bump foil stiffness model is not exact for large foil compliance ∼0.5, especially for lift-off speed analysis, due to ignoring the interaction between bumps and bending stiffness of the foil.

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