Step Response of Hydrostatic Thrust Bearings With a Self-Controlled Restrictor Employing a Floating Disk

1994 ◽  
Vol 116 (1) ◽  
pp. 154-160 ◽  
Author(s):  
S. Yoshimoto ◽  
Y. Anno ◽  
T. Kanemoto
Keyword(s):  
Thrust Bearing ◽  
Step Response ◽  
Design Parameters ◽  
Thrust Bearings ◽  
Response Characteristics ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Bearing Stiffness ◽  
Range Of Values ◽  
Very High

This paper describes the step response of a hydrostatic thrust bearing with a self-controlled restrictor employing a floating disk. This type of bearing can achieve a very high static bearing stiffness by controlling the mass flow rate of the fluid entering the bearing clearance, using the floating disk. Many parameters affect the step-response characteristics of this type of bearings. Influences of each parameter on the step response are theoretically investigated, and theoretical and experimental results are compared in order to verify the theoretical predictions. It was consequently found that the step response of this hydrostatic thrust bearing with the self-controlled restrictor was stable over a wide range of values of design parameters.

Step Response Characteristics of Hydrostatic Journal Bearings With Self-Controlled Restrictors Employing a Floating Disk

1999 ◽  
Vol 121 (2) ◽  
pp. 315-320 ◽  
Author(s):  
S. Yoshimoto ◽  
K. Kikuchi
Keyword(s):  
Static Load ◽  
Journal Bearings ◽  
Step Response ◽  
Design Parameters ◽  
Static Stiffness ◽  
Load Direction ◽  
Response Characteristics ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Very High

This paper describes the step response characteristics of hydrostatic journal bearings with self-controlled restrictors employing a floating disk. This type of bearing can achieve very high static stiffness by controlling the mass flow rate of the fluid entering the bearing clearance using a floating disk. Many design parameters such as supply pressure, viscosity, the magnitude of the step load and the imposed static load affect the step response characteristics of the proposed bearing. Therefore, the influences of each design parameter on the step response characteristics are theoretically investigated in this paper. Furthermore, the theoretical results are compared with the experimental results in order to verify the theoretical predictions. It is subsequently found that the proposed bearing consistently shows a stable step response irrespective of the step-load direction.

Static Characteristics of a Rectangular Hydrostatic Thrust Bearing With a Self-Controlled Restrictor Employing a Floating Disk

1993 ◽  
Vol 115 (2) ◽  
pp. 307-311 ◽  
Author(s):  
S. Yoshimoto ◽  
Y. Anno ◽  
M. Fujimura
Keyword(s):  
Flow Rate ◽  
Applied Load ◽  
Thrust Bearing ◽  
Static Characteristics ◽  
Hydrostatic Bearing ◽  
Supply Pressure ◽  
Wide Range ◽  
Bearing Stiffness ◽  
New Type ◽  
Very High

This paper proposes a new type of a self-controlled restrictor which can achieve a very high bearing stiffness in hydrostatic bearings. This self-controlled restrictor employs a floating disk to control the mass flow rate of the oil entering the bearing clearance according to changes of the applied load. Furthermore, a hydrostatic bearing with this restrictor can theoretically achieve an infinite stiffness when the mass of a floating disk is assumed to be zero. The static characteristics of a rectangular hydrostatic thrust bearing with this self-controlled restrictor are theoretically and experimentally investigated. It was consequently shown that the proposed hydrostatic thrust bearing can achieve a very high stiffness (nearly infinite stiffness) in a very wide range of applied load independent of supply pressure.

Gas Purging System to Extend Thrust Bearing Life in ESPs

2021 ◽  
Author(s):  
Jose Caridad ◽  
Arthur Watson ◽  
Song Shang ◽  
Eric Nguyen ◽  
Gocha Chochua
Keyword(s):  
Thrust Bearing ◽  
Operating Conditions ◽  
Design Parameters ◽  
Motor Oil ◽  
Oil Viscosity ◽  
Test Fixture ◽  
Thrust Bearings ◽  
Working Volume ◽  
Gas Purging ◽  
Critical Components

Abstract Electric submersible pump (ESP) systems use thrust bearings in the seal section to handle the thrust generated by the pump stages. Thrust bearings are subjected to harsh operating conditions, including high loads, poor oil circulation, and motor oil viscosity degradation. A less-recognized issue is gas becoming centrifugally trapped under the thrust runner. The gas may be present because of incomplete purging of air during filling, permeation of well gas into the motor oil, or gradual gasification of motor oil at high temperatures. Because thrust bearings are such critical components, it is of interest to increase their reliability, which in turn will increase ESP life. A novel gas purging system (GPS) was designed to alleviate stressors on thrust bearings, including gas accumulation, viscosity deterioration and gasification at high temperature, and low working oil volume. GPS circulates oil along with any gas that accumulates under the thrust runner up to a quiet separation chamber. Degassed oil circulates back to the thrust bearing, while accumulated gas eventually purges to the wellbore through relief valves on subsequent on/off cycles. GPS also improves viscosity and reduces gasification by cooling the oil, and it provides a greater working volume of thrust bearing oil to reduce the effects of oil deterioration. This paper details the GPS design principles as well as the optimization of the different design parameters that affect its performance conducted via computational fluid dynamics (CFD). Observations captured on a test fixture built using the final configuration are also presented, validating the intended functionality.

Dynamic Analysis of High-Speed Hybrid Thrust Bearings

2013 ◽  
Vol 365-366 ◽  
pp. 304-308
Author(s):  
Lei Wang
Keyword(s):  
Dynamic Analysis ◽  
High Speed ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Dynamic Performance ◽  
Orifice Diameter ◽  
Thrust Bearings ◽  
Supply Pressure ◽  
Bearing Stiffness ◽  
Stiffness And Damping

An analysis is conducted and solutions are provided for the dynamic performance of high speed hybrid thrust bearing. By adopting bulk flow theory, the turbulent Reynolds equation is solved numerically with the different orifice diameter and supply pressure. The results show that increasing supply pressure can significantly improve the bearing stiffness and damping, while the orifice diameters make a different effect on the bearing stiffness and damping.

Numerical Study on Static and Dynamic Performances of a Double-Pad Annular Inherently Compensated Aerostatic Thrust Bearing

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Hui Zhuang ◽  
Jianguo Ding ◽  
Peng Chen ◽  
Yu Chang ◽  
Xiaoyun Zeng ◽  
...  
Keyword(s):  
Thrust Bearing ◽  
Numerical Study ◽  
Dynamic Mesh ◽  
Step Response ◽  
Orifice Diameter ◽  
Design Parameters ◽  
Machining Accuracy ◽  
Eccentricity Ratio ◽  
Mesh Method ◽  
Dynamic Performances

The performances of aerostatic bearings have an important impact on machining accuracy in the ultraprecision machine tools. In this paper, numerical simulation is performed to calculate the static and dynamic performances of a double-pad annular inherently compensated aerostatic thrust bearing, while considering the effects of the upper bearing and lower bearing. The static results calculated by the computational fluid dynamics (CFD) method are compared with the finite difference method (FDM) for the specific model. By using polynomial fitting, the load-carrying capacity (LCC) of the bearing is calculated and the relationship between eccentricity ratio, design parameters, and static stiffness is analyzed. The active dynamic mesh method (ADMM) is applied to obtain the dynamic performance of the double-pad aerostatic thrust bearing based on the perturbation theory. Meanwhile, the effects of supply pressure, orifice diameter, squeeze number, and eccentricity ratio are comprehensively considered. Moreover, the step response of the double-pad thrust bearing is analyzed by using the passive dynamic mesh method (PDMM) based on dynamic equation. Related dynamic parameters including natural frequency are obtained through a system identification toolbox with Matlab, which can be used to avoid resonance. It is found that the dynamic calculation results computed by the ADMM and the PDMM are very close. The proposed method can be used to provide guidance for the design and optimization of the double-pad aerostatic thrust bearings.

scholarly journals Theoretical Disquisition on the Static and Dynamic Characteristics of an Adaptive Stepped Hydrostatic Thrust Bearing with a Displacement Compensator

Mathematics ◽  
2021 ◽  
Vol 9 (22) ◽  
pp. 2949
Author(s):  
Vladimir Kodnyanko ◽  
Andrey Kurzakov ◽  
Olga Grigorieva ◽  
Maxim Brungardt ◽  
Svetlana Belyakova ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Metal Cutting ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Theoretical Research ◽  
Stable Operation ◽  
Adaptive Function ◽  
Main Bearing ◽  
Thrust Bearings ◽  
Wide Range

Stepped hydrostatic thrust bearings used in metal-cutting machines are characterized by high load capacity and damping, which ensure the stable operation of structures. However, in comparison with throttle thrust bearings, they have a high compliance. It is preferable that, in addition to the main bearing function, a modern hydrostatic bearing has the ability to provide low (including negative) compliance for the implementation of an adaptive function in order to actively compensate for the deformation of the machine resilient system, thereby increasing the accuracy of metalworking. This paper considers the design of a stepped hydrostatic thrust bearing, which, in order to reduce the compliance to negative values, features a technical improvement consisting of the use of an active displacement compensator on an elastic suspension. In this paper, the results of mathematical modeling and theoretical research of stationary and non-stationary modes of operation of the adaptive thrust bearing are presented. The possibility of a significant reduction in the static compliance of the structure, including the negative compliance values, is shown. It was found that negative compliance is provided in a wide range of loads, which can be up to 80% of the range of permissible bearing loads. The study of the dynamic characteristics showed that with a targeted selection of parameters that ensure optimal performance, the adaptive thrust bearing is able to operate stably in the entire range of permissible loads. It has been established that an adaptive stepped hydrostatic thrust bearing with a displacement compensator has a high stability margin, sufficient to ensure its operability when implementing the adaptive function.

An Experimental and Theoretical Study of Lubricant Film Extent and Flowrate in Grooved Rectangular Pad Slider Thrust Bearings

1984 ◽  
Vol 198 (4) ◽  
pp. 225-233
Author(s):  
D J Hargreaves ◽  
C M Taylor
Keyword(s):  
Theoretical Study ◽  
Journal Bearings ◽  
Lubricant Film ◽  
Accurate Assessment ◽  
Interface Position ◽  
Thrust Bearings ◽  
Analysis Scheme ◽  
Wide Range ◽  
The Reformation ◽  
Theoretical Predictions

In liquid lubricated journal bearings an accurate assessment of the flowrate requires detailed consideration of the extent of the cavitated or ruptured region. Particular difficulties are encountered analytically when attempting to locate the boundary where the lubricant film reforms, normally in the vicinity of a supply groove. Most bearing analyses omit a consideration of this reformation boundary because of such difficulties. However, it is now widely recognized that the prediction of flowrate may be seriously in error if reformation effects are not incorporated in the analysis. In the present paper an externally pressurized, grooved, rectangular pad, slider hearing is examined. An air-lubricant interface may form in such a bearing which is akin to the reformation boundary encountered in journal bearings. A numerical analysis scheme to locate the interface is described in detail and theoretical predictions of bearing flowrate and interface position presented for a wide range of conditions. A comparison of the analytical predictions with experimental measurements is undertaken.

Optimization of Groove Geometry for Thrust Air Bearing to Maximize Bearing Stiffness

2007 ◽  
Author(s):  
Hiromu Hashimoto ◽  
Masayuki Ochiai ◽  
Tadashi Nanba
Keyword(s):  
High Speed ◽  
Design Methodology ◽  
Logarithmic Spiral ◽  
Load Carrying Capacity ◽  
Air Bearing ◽  
Thrust Bearings ◽  
Load Carrying ◽  
Bearing Stiffness ◽  
The Stability ◽  
Very High

Hydrodynamic gas film bearings are widely used for very high speed, lightly loaded rotating machinery. In the design of hydrodynamic gas film bearings, it is of cardinal importance to enhance the stiffness of gas films for minimizing the vibration due to external excitations. Among various types of hydrodynamic gas film thrust bearings, grooved bearings have an advantage of high stiffness and load carrying capacity, but the stiffness of the bearings strongly depends on groove geometry. Therefore, when the groove geometry is designed suitably, it is expected to improve considerably the stability characteristics of the bearings. However, the conventional bearing geometries are based on the fixed logarithmic spiral curve, and there is no literature treating how to change effectively the groove geometry to improve drastically the bearing characteristics. In this paper, the entirely new optimum design methodology, in which the groove geometry can be changed flexibly by using the spline function, is presented to maximize the stiffness of gas films for grooved thrust bearings, and the effectiveness of the methodology is verified experimentally.

Structural Optimization of Lattice Materials

2011 ◽  
Author(s):  
Andrea Vigliotti ◽  
Damiano Pasini
Keyword(s):  
Point Load ◽  
Design Parameters ◽  
Tissue Scaffold ◽  
Analysis And Design ◽  
Multiscale Mechanics ◽  
Lattice Materials ◽  
Wide Range ◽  
Macroscopic Properties ◽  
Energy Absorbing ◽  
Very High

Lattice materials are characterized at the microscopic level by a regular pattern of voids confined by walls. Recent rapid prototyping techniques allow their manufacturing from a wide range of solid materials, ensuring high degrees of accuracy and limited costs. The microstructure of lattice material permits to obtain macroscopic properties and structural performance, such as very high stiffness to weight ratios, highly anisotropy, high specific energy dissipation capability and an extended elastic range, which cannot be attained by uniform materials. Among several applications, lattice materials are of special interest for the design of morphing structures, energy absorbing components and hard tissue scaffold for biomedical prostheses. Their macroscopic mechanical properties can be finely tuned by properly selecting the lattice topology and the material of the walls. Nevertheless, since the number of the design parameters involved is very high, and their correlation to the final macroscopic properties of the material is quite complex, reliable and robust multiscale mechanics analysis and design optimization tools are a necessary aid for their practical application. In this paper, the optimization of lattice materials parameters is illustrated with reference to the design of a bracket subjected to a point load. Given the geometric shape and the boundary conditions of the component, the parameters of four selected topologies have been optimized to concurrently maximize the component stiffness and minimize its mass.

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