Effects of Grooving in a Hydrostatic Circular Step Thrust Bearing With Porous Facing

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
M. Mahbubur Razzaque ◽  
M. Zakir Hossain
Keyword(s):  
Mathematical Model ◽  
Inclination Angle ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Seepage Flow ◽  
Groove Depth ◽  
Small Thickness ◽  
Flow Through ◽  
High Level

Effects of grooving in a porous faced hydrostatic circular step thrust bearing are investigated using a mathematical model based on the narrow groove theory (NGT). It is shown that enhancement of load capacity by grooving the step is possible at moderate level of permeability of the porous facing. Load capacity drops sharply with the increase of porous facing thickness. However, this drop in load capacity occurs mostly within a small thickness of the porous facing. Considering the coupled effects of permeability and inertia, it is recommended that the dimensionless step location should be 0.5–0.8 and the dimensionless step height should be less than five to take advantage of grooving. The groove geometric parameters such as groove inclination angle, fraction of grooved area and groove depth corresponding to the maximum load capacity are found to be the same for both with and without porous facing. However, with porous facing, the sensitivity of the load capacity on the groove parameters reduces. At high level of permeability, the effects of grooves may become insignificant because of high seepage flow through the porous facing.

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.

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.

The Optimal Design of Multi-Level Planetary Gear Reducer

2010 ◽  
Vol 139-141 ◽  
pp. 1308-1311 ◽  
Author(s):  
Jing Bing Wu ◽  
Lun Shu ◽  
He Ming Cheng
Keyword(s):  
Mathematical Model ◽  
Optimal Design ◽  
Load Capacity ◽  
Planetary Gear ◽  
Maximum Load ◽  
Practical Design ◽  
Optimal Function ◽  
Multi Level ◽  
The Mathematical Model ◽  
Center Distance

Based on the analysis and study of the composite reducer, the allocation of transmission ratio is considered to be the key to optimal design of multi-level planetary gear reducer. In view of so many discussion and study of the minimum volume as the optimization objective existed, this paper regards the maximum load capacity as the optimal goal on condition that the center distance or size is given, and then establishes the optimal mathematical model. The related constraints are given according to the theoretical knowledge and practical design experience. In this paper, an optimal function procedure that based on genetic is used to optimize the mathematical model. The satisfied result has been worked out combined with the practical example. Compared to the original program, the load capacity of 17.8% is improved. In addition, some references are provided to the optimal design of planetary gear reducer.

Gas-lubricated sector thrust bearing with maximum load capacity

1991 ◽  
Vol 25 (6) ◽  
pp. 838-845 ◽  
Author(s):  
Yu. Ya. Boldyrev ◽  
Yu. V. Borisov
Keyword(s):  
Thrust Bearing ◽  
Load Capacity ◽  
Maximum Load

Thermal Distortion of Spiral-Grooved Gas-Lubricated Thrust Bearings

1971 ◽  
Vol 93 (1) ◽  
pp. 102-111 ◽  
Author(s):  
C. Wachmann ◽  
S. B. Malanoski ◽  
J. H. Vohr
Keyword(s):  
Thrust Bearing ◽  
Load Capacity ◽  
Heat Removal ◽  
Maximum Load ◽  
Thermal Distortion ◽  
Thrust Bearings ◽  
Self Heating ◽  
Worked Example ◽  
Performance Curves

Self-heating during operation causes a bearing to undergo thermal distortion. A method is presented to determine the consequent effects on the load capacity of a spiral-grooved air-lubricated thrust bearing designed for maximum load capacity. The effect of mode of heat removal is discussed. Appropriate performance curves and a worked example are given.

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 Tests on Tapered-Land and Pivoted-Shoe Thrust Bearings for Large Steam-Turbine Application

1959 ◽  
Vol 81 (2) ◽  
pp. 208-213
Author(s):  
R. E. Brandon ◽  
H. C. Bahr
Keyword(s):  
Bearing Capacity ◽  
Steam Turbine ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Full Scale ◽  
Thermal Distortion ◽  
Test Installation ◽  
Land Type ◽  
Thrust Bearings

Results of full-scale maximum load capacity tests on large, 3600-rpm, pivoted-shoe and tapered-land thrust bearings are reported. The results show 700 psi capacity for the pivoted-shoe bearing and 1085 psi for the tapered-land type. Additional evidence of thermal distortion and its effect on thrust-bearing capacity are discussed. A brief description of a new thrust-bearing test installation also is included.

A hydrodynamic lubrication model and comparative analysis for coupled microgroove journal-thrust bearings lubricated with water

2019 ◽  
Vol 234 (11) ◽  
pp. 1755-1770
Author(s):  
Guo Xiang ◽  
Yanfeng Han ◽  
Renxiang Chen ◽  
Jiaxu Wang ◽  
Xiaokang Ni ◽  
...  
Keyword(s):  
Thrust Bearing ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Mutual Effect ◽  
Hydrodynamic Pressure ◽  
Isosceles Triangle ◽  
Maximum Load ◽  
Hydrodynamic Effect ◽  
Thrust Bearings ◽  
Lubrication Performance

The novelty of this study is to develop a hydrodynamic lubrication numerical model for coupled microgroove journal-thrust bearings (or coupled bearings) under water-lubricated condition. In the present model, the continuity of the hydrodynamic pressure and the fluid field (or coupled hydrodynamic effect) at common boundary is considered to reveal the mutual effect between the hydrodynamic behavior of the journal bearing and the thrust bearing. The lubrication performances of the coupled microgroove bearing with three bottom shapes, i.e., isosceles triangle, right triangle, and left triangle, are studied comparatively. Additionally, the effects of the microgroove depth on the lubrication performances of the coupled bearing are discussed. The present study reveals that the coupled hydrodynamic effect generated by the coupled bearing can improve the lubrication performance for both the journal and the thrust bearing. The microgroove with left triangle bottom shape yields the optimal lubrication performance as compared to the other two. There is an optimal groove depth that generates the maximum load capacity and the minimum friction coefficient for both the journal and the thrust bearing.

Optimum clearance of a gas hydrostatic thrust bearing with maximum load capacity

2000 ◽  
Vol 35 (4) ◽  
pp. 525-533 ◽  
Author(s):  
V. I. Grabovskii
Keyword(s):  
Thrust Bearing ◽  
Load Capacity ◽  
Maximum Load

Analysis of Aerostatic Thrust Bearing for S-CO2 Turbomachinery

2019 ◽  
Author(s):  
Ashutosh Patel ◽  
Aanand K. Balasubramanian ◽  
Vijay Biradar ◽  
Shreyas Srivatsa ◽  
Pramod Kumar ◽  
...  
Keyword(s):  
High Speed ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Computational Domain ◽  
Axial Loads ◽  
Axial Thrust ◽  
Adiabatic Flow ◽  
Power Cycle ◽  
Flow Through ◽  
Thrust Pad

Abstract Preliminary analysis for the S-CO2 Brayton power cycle development suggests small size and high operating speed of turbomachinery. The axial thrust due to the pressure differential generated in the turbomachinery is transferred to the bearing through the shaft. Angular contact ceramic bearings used for high speed operations are incapable of withstanding high axial loads. The current paper presents, theoretical and computational analysis of a 4-hole aerostatic thrust bearing for S-CO2 turbomachinery applications. CFD analysis is performed for different axial clearance gap between stationary and rotating discs of the thrust bearing. The computations have been performed for two different fluids — air and CO2. This computational domain of the flow regime splits into two regions: adiabatic flow through the orifice and isothermal flow in the clearance volume comprising the clearance gap. The influence of the following parameters such as, pressure distribution across thrust pad area, mass flow rate, load capacity and the local velocity in the gap on the stiffness of the bearing are investigated.

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