The Stepped Thrust Bearing—A Solution by Relaxation Methods

1954 ◽  
Vol 21 (1) ◽  
pp. 19-24
Author(s):  
C. F. Kettleborough
Keyword(s):  
Thrust Bearing ◽  
Load Capacity ◽  
Analytical Investigation ◽  
Alternative Solution ◽  
Bearing Surface ◽  
Relaxation Methods

Abstract Analytical investigation into the stepped thrust bearing was first carried out by Lord Rayleigh, whose solution neglected side leakage. More recently Archibald has presented a solution with side leakage not neglected but limited by the step being straight across the bearing surface perpendicular to the direction of motion. This paper gives an alternative solution, using relaxation methods, which is applicable to any shape of the step. Results show that the load capacity of the completely internal step is much greater than that for the simple tilting slider.

Application of Materials on Foil Thrust Bearings for Micro Turbines

2011 ◽  
Vol 201-203 ◽  
pp. 2759-2762
Author(s):  
Quan Zhou ◽  
Yu Hou ◽  
Ru Gang Chen
Keyword(s):  
Thrust Bearing ◽  
Load Capacity ◽  
Bearing Surface ◽  
Thrust Bearings ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Soft Surface ◽  
Static Part ◽  
Micro Turbine ◽  
Foil Thrust Bearing

Foil bearing that has a soft surface is a kind of air bearing. The performances of foil bearings are greatly affected by the materials of bearing surface, which is called foil element. In order to estimate the performance of foil bearings, two kinds of foil thrust bearings that are made of different materials respectively were tested in a micro turbine system, which contains rotation part and static part. Load capacity and stability of these foil thrust bearings were investigated in experiments. The results show that bearing which contains rubber has higher load capacity and bearing which contains copper foil has higher stability. According to the work in this paper, applications with different requirements can adopt suitable foil thrust bearing.

Effects of Grooving in a Circular Step Thrust Bearing

2005 ◽  
Author(s):  
M. Mahbubur Razzaque ◽  
M. Zakir Hossain
Keyword(s):  
Pressure Distribution ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Outer Radius ◽  
Hydrodynamic Load ◽  
Bearing Surface ◽  
Lubricant Flow ◽  
Inner Radius ◽  
Minimum Film Thickness

Assuming narrow grooves and considering inertia effect, an equation for the pressure distribution in a grooved circular step thrust bearing has been derived. A parametric study has been performed to investigate the effects of step and groove geometry on pressure distribution, load capacity and lubricant flow rate. Three arrangements of the bearing surface have been studied and it has been found that the maximum load capacity is obtained by putting grooves only on the step. Inertia significantly affects the load capacity. To get increased load capacity with increase of inertia, the step inner radius should be larger than 0.45 times of the outer radius. For the most enhancement of hydrodynamic load, the groove inclination angle should be 135° with the direction of rotation and the depth should be twice the minimum film thickness.

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.

Numerical and experimental studies on the thermal and static characteristics of multi-leaf foil thrust bearing

2021 ◽  
pp. 135065012110110
Author(s):  
Yu Guo ◽  
Yu Hou ◽  
Qi Zhao ◽  
Xionghao Ren ◽  
Shuangtao Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Failure Process ◽  
Experimental Studies ◽  
Elastic Model ◽  
Static Characteristics ◽  
Bearing Load ◽  
Foil Thrust Bearing ◽  
Cooling Air

Foil bearing is considered to be a promising supporting technology in high-speed centrifugal machinery. Due to the high-speed shearing effect in the viscous lubricant film, heat generation could not be ignored. In this paper, a thermo-elastic model of the multi-leaf foil thrust bearing is proposed to predict its thermal and static characteristics. In the model, modified Reynolds equation, energy equation, and Kirchhoff equation are solved in a coupling way. The contact area between the foil and welding plate is taken into account. Besides, the effect of cooling air on the bearing temperature is investigated. The ultimate load capacity and transient overload failure process of the bearing is analyzed and discussed. The effect of rotation speed on the bearing temperature is more obvious than that of the bearing load. The bearing temperature drops obviously by introducing the cooling air, and the cooling effect is improved with the supply pressure. The transient overload failure of the bearing occurs when the bearing load exceeds the ultimate value.

An Accurate Solution of the Gas Lubricated, Flat Sector Thrust Bearing

1977 ◽  
Vol 99 (1) ◽  
pp. 82-88 ◽  
Author(s):  
I. Etsion ◽  
D. P. Fleming
Keyword(s):  
Film Thickness ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Thickness Distribution ◽  
Maximum Load ◽  
Accurate Solution ◽  
Operating Conditions ◽  
Thrust Bearings ◽  
Practical Design ◽  
Minimum Film Thickness

A flat sector shaped pad geometry for gas lubricated thrust bearings is analyzed considering both pitch and roll angles of the pad and the true film thickness distribution. Maximum load capacity is achieved when the pad is tilted so as to create a uniform minimum film thickness along the pad trailing edge. Performance characteristics for various geometries and operating conditions of gas thrust bearings are presented in the form of design curves. A comparison is made with the rectangular slider approximation. It is found that this approximation is unsafe for practical design, since it always overestimates load capacity.

Nanoparticles-Laden Gas Film in Aerostatic Thrust Bearing

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Zhiru Yang ◽  
Dongfeng Diao ◽  
Xue Fan ◽  
Hongyan Fan
Keyword(s):  
Effective Viscosity ◽  
Flow Model ◽  
Thrust Bearing ◽  
Volume Fraction ◽  
Load Capacity ◽  
Sio2 Nanoparticles ◽  
Enhancement Effect ◽  
The Novel ◽  
Two Phase ◽  
Air Film

Nanoparticles-laden gas film (NLGF) was formed by adding SiO2 nanoparticles with volume fraction in the range of 0.014–0.330% and size of 30 nm into the air gas film in a thrust bearing. An effective viscosity of the gas-solid two phase lubrication media was introduced. The pressure distribution in NLGF and the load capacity of the thrust bearing were calculated by using the gas-solid two phase flow model with the effective viscosity under the film thicknesses range of 15–60 μm condition. The results showed that the NLGF can increase the load capacity when the film thickness is larger than 30 μm. The mechanism of the enhancement effect of load capacity was attributed to the increase of the effective viscosity of the NLGF from the pure air film, and the novel lubrication media of the NLGF can be expected for the bearing industry application.

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.

Behavior of Thermal Effects and Velocity-Slip on Performance of Externally Pressurized Porous Incompressible Gas Thrust Bearing

1979 ◽  
Vol 46 (2) ◽  
pp. 465-468 ◽  
Author(s):  
V. K. Kapur ◽  
J. S. Yadav
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Effects ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Velocity Slip ◽  
Experimental Results ◽  
Slip Condition ◽  
Static Stiffness

In the present analysis, the interactions of thermal effects and velocity slip on the performance of externally pressurized porous incompressible gas thrust bearing have been studied. Numerical results for load capacity, mass flow rate, and static stiffness have been obtained and their behavior is illustrated in figures. The results for slip as well as no-slip condition have also been compared with the experimental results of Gargiulo and Gilmour [7].

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.

Centrifugal Effects in Hydrostatic Porous Thrust Bearing

1979 ◽  
Vol 101 (3) ◽  
pp. 381-385 ◽  
Author(s):  
R. S. Gupta ◽  
V. K. Kapur
Keyword(s):  
Pressure Distribution ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Bearing Material

In this analysis the customary neglected centrifugal effects on the performance of hydrostatic porous thrust bearing with incompressible lubricant has been studied and the effects of their interaction of pressure distribution and load capacity illustrate the possibility of replacement of the nonporous bearing material by porous one.

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