Hydrostatic Journal Bearing With Porous Pads and Improved Properties

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Dein Shaw ◽  
Hui-An Hsieh
Keyword(s):  
Theoretical Model ◽  
Flow Rate ◽  
Cylindrical Surface ◽  
Journal Bearing ◽  
Load Capacity ◽  
Simulation Software ◽  
Rotating Speed ◽  
Hydrostatic Bearing ◽  
Flow Through ◽  
Hydrodynamic Effects

Abstract A hydrostatic journal bearing with porous pads to improve its performance is designed. The porous pads, which are embedded in recesses of the hydrostatic journal bearing, not only allow lubricant to flow through them but also form a complete cylindrical surface with the bearing land. The load capacity of the hydrostatic bearing is thus maintained and the hydrodynamic effects strengthened. A theoretical model of the porous pads bearing is tested with the simulation software, and the parameters that critically affect the bearing performance are studied. Thus, the results obtained indicate that the porous pads bearing has higher load capacity and higher stiffness than a typical hydrostatic bearing with lower friction and lower end flow rate at high rotating speed.

Paper 10: A Hydrodynamic Pocket Journal Bearing

1969 ◽  
Vol 184 (12) ◽  
pp. 70-74
Author(s):  
D. F. Sheldon ◽  
J. P. O'Donoghue ◽  
C. J. Hooke
Keyword(s):  
High Pressure ◽  
Journal Bearing ◽  
Load Capacity ◽  
Control Device ◽  
Experimental Results ◽  
Alternative Mode ◽  
Hydrostatic Bearing ◽  
Operating Range ◽  
Mode Of Operation ◽  
Return Valve

The authors present theoretical and experimental results for a hydrodynamic pocket bearing. The bearing has a geometry similar to that of a conventional hydrostatic bearing, but no control device is incorporated in the supply line other than a non-return valve which prevents the leakage of fluid from those pockets where a pressure is generated. The load capacity of such bearings is greater than that of a circumferentially grooved hydrostatic bearing over the operating range of eccentricity tested by the authors, and is much greater than that of two short hydrodynamic bearings equal to the side sealing lands. Because of this the bearing offers a useful alternative mode of operation for a bearing (externally pressurized) which suffers a loss of its high-pressure oil supply.

Analysis on slot-type casing treatment injection flow in an axial transonic compressor

2016 ◽  
Vol 230 (8) ◽  
pp. 792-804 ◽  
Author(s):  
Mingmin Zhu ◽  
Xiaoqing Qiang ◽  
Wensheng Yu ◽  
Jinfang Teng
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Axial Direction ◽  
Stall Margin ◽  
Rotating Speed ◽  
Casing Treatment ◽  
Transonic Compressor ◽  
Injection Flow ◽  
Flow Through

The purpose of this work is to understand the properties of the injection flow through slots opening surfaces with steady and unsteady simulations. The feasibility of evaluating slot effectiveness by steady results is demonstrated. Transient features of injection flow are detailed investigated. Numerical investigations are carried out in a 1.5 axial transonic compressor stage at a specified rotating speed with seven kinds of slot-type casing treatments. Comparisons between steady/unsteady results show that differences of overall performance and injection mass flow rate are dependent on simulation methods, rather than slot configurations. Thus, correlation analysis by steady results of seven slot configurations is considered valid and reveals strong linear correlation between injection mass flow and stall margin improvements/efficiency drops. Therefore, it is practical to evaluate the effectiveness of a specific slot configuration in this compressor with steady results by calculating injection mass flow rate. Afterwards, unsteady simulations are performed with a specific configuration of arc-curve skewed slots. It is clarified that the dividing locations between suction/injection regions moves along the axial direction based on the relative rotor/slots location. Exchanging flow through slots opening surfaces displays periodic variations over time. The variation cycle for one single slot equals blade passing period T. For summation of mass flow through all slots, the cycle equals to T divided by slots number in one passage. The net flow rate through all opening surfaces is always less than zero during a blading passing period, i.e. injection mass flow rate is larger than suction flow all the time.

Master and Slave Hydrostatic Bearing Systems for Machine Tools

1966 ◽  
Vol 8 (2) ◽  
pp. 152-161 ◽  
Author(s):  
G. P. Kearney
Keyword(s):  
Machine Tools ◽  
Journal Bearing ◽  
Load Capacity ◽  
Design Procedure ◽  
High Load ◽  
General Analysis ◽  
Hydrostatic Bearing ◽  
Hydrostatic Bearings ◽  
Design Calculations ◽  
High Load Capacity

Master and slave systems utilize two types of hydrostatic bearing in order to provide high load capacity in conjunction with non-redundant location by rigid-film hydrostatic bearings. Master bearings are controlled both by applied thrust and by their clearance, and they also control the thrust in the slave bearings which act independently of their own clearances. A journal bearing is used to illustrate analysis of bearing systems, redundant locations, and master and slave systems. A general analysis of master and slave systems is given and a design procedure, advantages, fields of application, and design calculations for individual bearings are outlined in the text and appendixes.

The Vane Bearing—A Self-Pressurizing Journal Bearing

1975 ◽  
Vol 189 (1) ◽  
pp. 99-106 ◽  
Author(s):  
C. Ettles
Keyword(s):  
Theoretical Analysis ◽  
Journal Bearing ◽  
Load Capacity ◽  
Vane Pump ◽  
Power Requirement ◽  
Displacement Effect ◽  
Oil Film ◽  
Hydrostatic Bearing ◽  
Positive Displacement ◽  
Exit Port

If the shaft of a journal bearing could be made to have a number of pressure sources which travel with the shaft, the load capacity of the oil film could be greatly enhanced. This paper describes the development of a concept in which the pressure sources arise from a positive displacement effect due to the eccentricity of the shaft within the bearing. The configuration has similarities to the rotor of a vane pump in which the entry port is open and the exit port closed. The bearing could be described as a hybrid hydrodynamic-hydrostatic bearing where the hydrostatic supply is self-contained and self-generated. A number of methods of causing this self-pressurization are discussed. A theoretical analysis shows that load (or Sommerfeld) number improvement factors in the range 3–10 are quite feasible at the expense of an increased flow and power requirement.

Investigations in Hydrostatic Planar Bearings Compensated by Tapered-Spool Restrictors I: Flow Rate

2015 ◽  
Vol 32 (1) ◽  
pp. 63-69
Author(s):  
Y. Kang ◽  
H.-C. Cheng ◽  
C.-W. Lee ◽  
S.-Y. Hu
Keyword(s):  
Flow Rate ◽  
Analytical Method ◽  
Pressure Difference ◽  
Load Capacity ◽  
Design Parameters ◽  
Static Characteristics ◽  
Static Stiffness ◽  
Flow Rates ◽  
Single Action ◽  
Hydrostatic Bearing

ABSTRACTThis paper is former part of serial studies to investigate the influence of design parameters of tapered-spool type restrictors on static characteristics of hydrostatic bearing. The flow rates passing restrictors can determine the static characteristics of hydrostatic bearings. In this part an analytical method which includes formulas and solving is utilized to simulate dimensionless flow rate in both single-action and double-action tapered-spool restrictors. The numerical results illustrate the variations of flow rates with respect to the change of pressure and pressure difference, respectively. The findings give that the design parameters of tapered-spool restrictors and the useful range of recess pressure. The following part will depend on this paper results to study load capacity and static stiffness of hydrostatic bearing compensated by tapered-spool restrictor.

Pad attitude adjusting moment in large multi-pocket pivoted pad used in static oil journal bearing

2017 ◽  
Vol 69 (4) ◽  
pp. 605-611
Author(s):  
Xizhi Ma ◽  
Miaomiao Li
Keyword(s):  
Flow Rate ◽  
Ball Mill ◽  
Large Scale ◽  
Journal Bearing ◽  
Operating Conditions ◽  
Content Type ◽  
Oil Film ◽  
Hydrostatic Bearing ◽  
Attitude Adjustment ◽  
Oil Flow

Purpose Large scale is a trend of the ball mill, so the loads on their bearings become very large, bearing operating conditions turn into more severe. The moment of inertia to their pivot of the pad increase significantly, so it leads to the difficult of the pad attitude adjustment and makes the pad tilting angles time response slow, the key factor to effects attitude adjustment is the oil film moment to the pad pivot at unbalance position. the oil film moment and its effect factors must be studied in the design of the bearing used in ball mill. Design/methodology/approach Models about the lubrication of multi-pocket pivoted pad hydrostatic bearing is established, the complicated relationship of the oil flow rate between the oil pockets are taken into account. Finite differential method is used to solv the model, and theroy of finite element method is use to calculate the oil flow rate out of the pocket edges. Newton’s methods are used to determine the pressure of pockets.The pad tilting moment to its pivot is numerically analyzed. Findings The tilting moment to its pivot is set as an indicator of the ability for a pad to adjust its attitude. The effects of the diameter of throttling capillary and the pocket area on the attitude adjusting capacity is studied. Relations between the attitude adjustment capacity for a pad and there effects factors are presented. Practical implications The methods and results have the special reference to the design and operation of multiple pockets tilted pad hydrostatic journal bearing. Originality/value Methods to studied the pad attitude adjustment are given in the article for the multi-pocket pivot pad hydrostatic beairng.The influence factors on pad attitude adjusting capacity are discussed for a this specail kind hydrostatic bearing, the how the factors influence the pad tilting angle adjustment are presented.

scholarly journals Prediction on Flow and Thermal Characteristics of Ultrathin Lubricant Film of Hydrodynamic Journal Bearing

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1208
Author(s):  
Yulong Jiang ◽  
Bo Liang ◽  
Zhongwen Huang ◽  
Zhenqian Chen ◽  
Bo Xu
Keyword(s):  
Flow Rate ◽  
Heat Dissipation ◽  
Journal Bearing ◽  
Thermal Characteristics ◽  
Lubricant Film ◽  
Rotating Speed ◽  
Slip Boundary ◽  
Theoretical Support ◽  
Hydrodynamic Journal Bearing ◽  
Temperature Liquid

This paper focuses on the flow and thermal characteristics of the lubricant film in the micro clearance of a hydrodynamic journal bearing (HJB) at high rotating speed. A thermohydrodynamic (THD) method consists of the Reynolds equation coupled with energy and viscosity-temperature equation with considering the cavitation is put forward. The 3D surface diagrams of the lubricant film thickness, pressure, temperature, liquid mass fraction, flow rate and heat dissipation distributions under different geometric, operating, slip and no-slip boundary conditions are systemically exhibited and analyzed. The results show that with the rise of eccentricity or length diameter ratio, the maximum peaks of pressure, temperature and heat dissipation are rapidly increased, the cavitation is aggravated, and the flow rate is accelerated in different extent. As the bearing speed accelerating, the maximum peak of temperature is strongly increased, whereas, the distinction between peaks of flow rate and heat dissipation is magnified and reduced, respectively. It provides a fruitful inside view of the inner flow and thermal characterizations of HJB for further understanding its flow-thermal interaction mechanisms and offers theoretical support for improving its working performance.

Static performance of the aerostatic journal bearing with grooves

2019 ◽  
Vol 234 (7) ◽  
pp. 1114-1130
Author(s):  
Xinglong Chen ◽  
James K Mills ◽  
Gang Bao
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Journal Bearing ◽  
Load Capacity ◽  
Groove Depth ◽  
Load Force ◽  
Orifice Diameter ◽  
Geometrical Parameters ◽  
Gas Flow Rate ◽  
Static Performance

Aerostatic bearings are widely employed in precision machines due to their properties of low friction, low heat conduction, and long-life operation. In this work, static performance of the journal bearing with rectangular grooves is investigated numerically. The effect of geometrical parameters such as axial groove length [Formula: see text], circumferential groove length [Formula: see text], orifice diameter df, groove depth gh, misalignment angles [Formula: see text] and [Formula: see text] on the load capacity [Formula: see text], stiffness [Formula: see text], and gas flow rate [Formula: see text] are analyzed systematically. The resistance network method (RNM) is utilized to solve the Reynolds equation required in the analysis. Performance parameters including pressure distribution P, load force [Formula: see text], stiffness [Formula: see text], and gas flow rate [Formula: see text] are examined in the simulations. It is revealed from the simulations that the proper value of axial groove length [Formula: see text] to obtain a better static performance varies from 1/8 to 1/2 when df varies between 0.11 and 0.29 mm, respectively. Therefore, a larger load force and stiffness can be obtained if [Formula: see text] is chosen to be 1/4, when diameter of the bearing orifice df equals 0.17 mm. It is also suggested that [Formula: see text] be chosen from the range of 1/6 and 1/3 to obtain a better static performance and a smaller gas flow rate. [Formula: see text] decreases with an increase in df when [Formula: see text] is set to be 1/8. However, the load force [Formula: see text] increases with an increase in df when [Formula: see text] varies from 3/8 to 1/2. [Formula: see text] has a significant influence on the changes of [Formula: see text] with df when [Formula: see text] is set to be constant. Therefore, df should be selected according to [Formula: see text] for an optimal design. The increase of misalignment angle [Formula: see text] leads to an increase in the load force [Formula: see text]. [Formula: see text] has little influence on the load force [Formula: see text]. Misalignment angles [Formula: see text] and [Formula: see text] have little influence on stiffness [Formula: see text] and gas flow rate [Formula: see text]. Therefore, it is preferable if [Formula: see text] is larger than 0 rad.

Steady State Performance of a Hydrodynamic Journal Bearing With a Pseudoplastic Lubricant

1979 ◽  
Vol 101 (4) ◽  
pp. 497-502 ◽  
Author(s):  
C. Rajalingham ◽  
B. S. Prabhu ◽  
B. V. A. Rao
Keyword(s):  
Steady State ◽  
Flow Rate ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Slenderness Ratio ◽  
Correlation Effect ◽  
Polynomial Type ◽  
Successive Over Relaxation ◽  
Steady State Performance

Starting from the general shear stress-shear strain relation of the odd cubic polynomial type considering correlation effect for pseudoplastic (shear thinning) lubricant, a modified form of Reynolds’ equation (nonlinear) is derived under conventional hydrodynamic lubrication approximations. The finite difference technique with successive over relaxation is used adopting the solution of the associated linear equation as a first approximation to obtain the pressure distribution of a finite cylindrical journal bearing incorporating Reynolds’ boundary conditions. Steady state performance characteristics such as load capacity, attitude, friction and flow rate are obtained for various values of nonlinear parameter and bearing slenderness ratio. The results presented in nondimensional form are compared with established results for Newtonian lubricants. The investigation shows a significant effect of correlation on the bearing load capacity and flow rate.

scholarly journals Optimization of Conical Hydrostatic Bearing for Minimum Friction

1972 ◽  
Vol 94 (2) ◽  
pp. 136-142 ◽  
Author(s):  
L. J. Nypan ◽  
B. J. Hamrock ◽  
H. W. Scibbe ◽  
W. J. Anderson
Keyword(s):  
Laminar Flow ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Turbulent Flows ◽  
Flow Rate ◽  
Load Capacity ◽  
Friction Torque ◽  
Radius Ratio ◽  
Hydrostatic Bearing ◽  
Laminar And Turbulent Flow

Equations for the flow rate, load capacity, and friction torque for a conical hydrostatic bearing were developed. These equations were solved by a digital computer program to determine bearing configurations for minimum friction torque. Design curves are presented that show optimal bearing dimensions for minimum friction torque as a function of dimensionless flow rate for a range of dimensionless load capacity. Results are shown for both laminar and turbulent flow conditions. The results indicate the hydrostatic pocket friction is a significant portion of the total friction torque. However, the bearing dimensions for a minimum friction design are affected very little by inclusion of pocket friction in the analysis. For laminar flow the values of the outerland radius ratio X3 and outer bearing radius ratio X4 did not change significantly with increasing friction factor. For turbulent flow, the outer bearing radius ratio X4 did not change with increasing friction factor; therefore, the value determined for X4 in the laminar flow case is valid for all turbulent flows.

Sign in / Sign up

Export Citation Format

Share Document