scholarly journals Distributions of Hydrodynamic Pressure in the Gap of Slide Journal Bearing Lubricated with Ferro-Oil

2019 ◽  
Vol 26 (4) ◽  
pp. 53-61
Author(s):  
Marcin Frycz
Keyword(s):  
Magnetic Particles ◽  
Journal Bearing ◽  
Research Work ◽  
Hydrodynamic Pressure ◽  
Qualitative And Quantitative Analysis ◽  
Oil Viscosity ◽  
Temperature Changes ◽  
Pressure Distributions ◽  
Pressure Changes ◽  
The Magnetic Field

AbstractThis research work is part of a broader comprehensive issue, which is the analysis of flow and operating parameters of journal slide bearings lubricated with ferro-oil. In this article, the author presents only the main assumptions and essential transformations of the analytical and numerical model for determining the pressure distributions in the gap of a slide journal bearing lubricated with ferro-oil. It is cardinal that the rheological and magnetic values of ferro-oil parameters adopted in numerical calculations are based on the results of actual values obtained in the author’s earlier research work. There are presented the pressure distributions by abovementioned method in the article for cases of bearings lubricated with ferro-oils with different concentration of magnetic particles. The obtained results are shown in the form of a set of four complementary characteristics of the dimensionless pressure distributions. First and main of them are the calculations for classical Newtonian lubrication but they take into account the influence of the magnetic field on the distributions. The next of the presented characteristics are so-called “corrections” of pressure distribution values, taking into account as follows: effects of changes in ferro-oil viscosity related to temperature changes, impacts of ferro-oil viscosity changes related to pressure changes and the effect of non-oil properties of the lubricant. The article includes a qualitative and quantitative analysis of the obtained results as well as observations and conclusions are presented in it.

THE EFFECT OF THE CONCENTRATION OF MAGNETIC PARTICLES ON THE OPERATING PARAMETERS OF A SLIDE JOURNAL BEARING LUBRICATED WITH FERRO-OIL

Tribologia ◽  
2019 ◽  
Vol 284 (2) ◽  
pp. 43-55
Author(s):  
Marcin Frycz
Keyword(s):  
Magnetic Particles ◽  
Journal Bearing ◽  
Calculation Model ◽  
Physical Parameters ◽  
Operating Parameters ◽  
Operational Parameters ◽  
Oil Viscosity ◽  
Temperature Changes ◽  
Load Carrying ◽  
Pressure Changes

This paper presents an analysis of changes in basic operational parameters of a slide journal bearing in an aspect of a concentration of magnetic particles in ferro-oil as a lubricant. The first part of the article presents an analytical-numerical calculation model. This model is based on experimentally determined physical parameters describing the dependence of ferro-oil viscosity on changes at basic operating parameters. Moreover, dimensionless load carrying capacity, dimensionless friction force and dimensionless coefficient of friction numerical calculations have been obtained by solving the Reynolds type equations using the finite difference method in Mathcad 15 program and the author’s own calculation procedures. The obtained results have been presented in the form of graphs taking into account the influence of the following factors: external magnetic field, corrections related to the influence of pressure changes, corrections related to the influence of temperature changes and corrections related to non-Newtonian properties of the ferro-oil. The analysis of the obtained characteristics in the paper has been carried out, observations have been made as well as conclusions have been drawn regarding the optimal concentration of magnetic particles in the ferro-oil lubricating the slide journal bearing.

Machine learning-based performance analysis of two-axial-groove hydrodynamic journal bearings

2021 ◽  
pp. 135065012199289
Author(s):  
Biswajit Roy ◽  
Sudip Dey
Keyword(s):  
Journal Bearing ◽  
Journal Bearings ◽  
Hydrodynamic Performance ◽  
Support Vector ◽  
Oil Viscosity ◽  
Hydrodynamic Analysis ◽  
Supply Pressure ◽  
Input Parameters ◽  
Precise Prediction ◽  
Output Behavior

The precise prediction of a rotor against instability is needed for avoiding the degradation or failure of the system’s performance due to the parametric variabilities of a bearing system. In general, the design of the journal bearing is framed based on the deterministic theoretical analysis. To map the precise prediction of hydrodynamic performance, it is needed to include the uncertain effect of input parameters on the output behavior of the journal bearing. This paper presents the uncertain hydrodynamic analysis of a two-axial-groove journal bearing including randomness in bearing oil viscosity and supply pressure. To simulate the uncertainty in the input parameters, the Monte Carlo simulation is carried out. A support vector machine is employed as a metamodel to increase the computational efficiency. Both individual and compound effects of uncertainties in the input parameters are studied to quantify their effect on the steady-state and dynamic characteristics of the bearing.

Magnetorheological fluid based on amorphous Fe-Si-B alloy magnetic particles

2021 ◽  
pp. 1045389X2110643
Author(s):  
Chuncheng Yang ◽  
Zhong Liu ◽  
Xiangyu Pei ◽  
Cuiling Jin ◽  
Mengchun Yu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Rheological Property ◽  
Magnetic Particles ◽  
Annealing Treatment ◽  
Magnetorheological Fluid ◽  
The Stability ◽  
The Magnetic Field ◽  
Amorphous Particle ◽  
Better Than

Magnetorheological fluids (MRFs) based on amorphous Fe-Si-B alloy magnetic particles were prepared. The influence of annealing treatment on stability and rheological property of MRFs was investigated. The saturation magnetization ( Ms) of amorphous Fe-Si-B particles after annealing at 550°C is 131.5 emu/g, which is higher than that of amorphous Fe-Si-B particles without annealing. Moreover, the stability of MRF with annealed amorphous Fe-Si-B particles is better than that of MRF without annealed amorphous Fe-Si-B particles. Stearic acid at 3 wt% was added to the MRF2 to enhance the fluid stability to greater than 90%. In addition, the rheological properties demonstrate that the prepared amorphous particle MRF shows relatively strong magnetic responsiveness, especially when the magnetic field strength reaches 365 kA/m. As the magnetic field intensified, the yield stress increased dramatically and followed the Herschel-Bulkley model.

scholarly journals Forensic Engineering Techniques For Testing And Predicting Lp-Gas Container Relief Venting

2004 ◽  
Vol 21 (2) ◽  
Author(s):  
James A. Petersen
Keyword(s):  
Test Data ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Pressure Relief ◽  
Temperature Changes ◽  
Flammable Gas ◽  
Forensic Engineering ◽  
Pressure Changes ◽  
Liquefied Gas

When An Lp-Gas Container Is Involved In A Fire, Flammable Gas Is Usually Vented From The Relief Valve. One Of The First Questions Is Whether The Container Vented The Gas That Caused The Fire Or Whether Gas Was Vented Due To The Fire Heating The Container. If The Relief Valve Vents Gas That Initiates The Fire, It Is Usually Due To An Overfilled Container. This Paper Discusses; 1) The Prediction Of The Rate Of Container Warming Due To Normal Temperature Changes, 2) The Resulting Pressure Changes Of The Liquefied Gas, 3) The Reaction Of The Pressure Relief Valve And The Quantity Of Lp-Gas Vented During The Operation Of The Relief Valve, 4) Designing The Experiment And 4) Adjusting The Model To Reflect Test Data.

scholarly journals An Experimental Validation Study of Ferrofluid Evaporation

2021 ◽  
Author(s):  
Wenjuan YU ◽  
Decai Li ◽  
Sifang Niu
Keyword(s):  
Base Fluid ◽  
Experimental Validation ◽  
Magnetic Particles ◽  
Evaporation Rate ◽  
Volume Fraction ◽  
Test Tube ◽  
Weight Losses ◽  
Lower Volume Fraction ◽  
Lower Volume ◽  
The Magnetic Field

Abstract Kerosene based ferrofluid was put into a test tube to evaporate under different conditions. The weight losses of samples were measured and the evaporation rates were calculated. The predictions of evaporation rates were made based on Bolotov’s model. It was found that the magnetic particles prevent the base fluid from evaporation and lower volume fraction leaded to higher evaporation rate. Bolotov’s model had a certain deviation but still well responsive to different variables. It was also found that the magnetic field made a difference to the evaporation rate.

Investigation of Squeeze Film Damper Forces Produced by Circular Centered Orbits

1978 ◽  
Vol 100 (1) ◽  
pp. 15-21 ◽  
Author(s):  
E. Feder ◽  
P. N. Bansal ◽  
A. Blanco
Keyword(s):  
Aircraft Engine ◽  
Analytical Investigation ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Oil Viscosity ◽  
Pressure Transducers ◽  
Pressure Distributions ◽  
Pressure Profiles ◽  
Force Components ◽  
Type Pressure

This paper presents the results of an experimental and analytical investigation of the dynamic forces generated by a squeeze film bearing damper constrained to move in circular centered orbits. These orbits were mechanically produced in a specially designed, end sealed, test rig. Aircraft engine damper geometry and operating conditions were simulated. The effect of journal speed, oil viscosity, inlet pressure, and eccentricity ratio on the damper performance was studied. The pressure distributions about the journal were measured for each test condition by high-response diaphragm-type pressure transducers. These pressure profiles were numerically integrated to determine the force components of the squeeze film. Experimental results were compared to an analysis which is summarized in this paper and included the effects of inlet and cavitation pressures. The “long bearing theory” was found to be reasonably accurate in predicting the shape and magnitude of the pressure distribution. Considerable emphasis was directed to the study of the circumferential pressure distributions between 180 deg and 360 deg since aircraft engine dampers generally operate in this region. For the cavitated film (i.e., pressure distributions less than 360 deg), accurate prediction of the damper forces was found to be critically dependent on the effect of inlet and cavitation pressures.

A Unified Theory for the Pressure Change of Sudden Expansions and Contractions Based on the Momentum Balance

2021 ◽  
Author(s):  
Sebastian Müller ◽  
Andreas Malcherek
Keyword(s):  
Control Volume ◽  
Pressure Change ◽  
Sudden Expansion ◽  
Momentum Balance ◽  
Unified Approach ◽  
Pressure Distributions ◽  
Analytical Functions ◽  
Specific Geometry ◽  
Control Volumes ◽  
Pressure Changes

Abstract In this paper a unified approach based on the momentum balance is presented, capable of predicting the pressure change of sudden contractions and sudden expansions. The use of empirically determined correction coefficients is not necessary. Therefore, the momentum balance is derived similarly for both applications but with different control volumes. The control volume takes into account the specific geometry of the hydraulic structure. With a properly chosen control volume, the unified approach requires coefficients that account for the velocity as well as pressure distributions on the boundaries of the control volume. These coefficients can be obtained by parameterizing the results of numerical simulations by simple analytical functions. The numerical model itself is validated by checking the simulated pressure change against calculated or measured pressure changes. It is found that the formulation of the momentum balance for the sudden expansion is more complex compared with the sudden contraction. The prediction of the pressure change of flows through sudden expansions can be improved by applying the momentum balance non-idealized. Most of the correction coefficients originate from an inappropriate application of Bernoulli’s energy conservation principle. Consequently, this leads to a gap between theory and experimental results. The proposed unified approach solely contains physical coefficients that are used to substitute integrals by averaged expressions.

Oil Flow in a Full Journal Bearing

1961 ◽  
Vol 83 (2) ◽  
pp. 312-314
Author(s):  
Donald F. Hays
Keyword(s):  
Flow Rate ◽  
Journal Bearing ◽  
Hydrodynamic Pressure ◽  
Leakage Rate ◽  
Positive Pressure ◽  
Pressure Gradients ◽  
Oil Film ◽  
Oil Flow ◽  
Pressure Area ◽  
Side Flow

An analysis was made of the oil flows occurring in a full journal bearing with a continuous oil film. The flow rate into the bearing was determined at the section of greatest clearance and the rate of outflow was determined at the section of least clearance. The rate of side flow or leakage rate was determined by considering the flow across the boundary of the positive pressure area only and is the flow resulting from the hydrodynamic pressure gradients. It does not include the effects of any specific oil feed mechanism.

A Novel Friction Model Basing on Journal Bearing Theory for Reciprocating Compressor

2013 ◽  
Vol 456 ◽  
pp. 320-323 ◽  
Author(s):  
Le Wang ◽  
Bin Tang ◽  
Yuan Yang Zhao
Keyword(s):  
Friction Coefficient ◽  
Piston Ring ◽  
Sliding Friction ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Dynamic Change ◽  
Friction Model ◽  
Reciprocating Compressor ◽  
Oil Viscosity ◽  
Compressor Performance

The paper presents a comprehensive friction model of reciprocating compressor which is able to evaluate friction losses in moving parts. The model consists of crankshaft, connecting rod and piston all supported by bearings as well as the piston ring/cylinder interface viewed as sliding friction. Hydrodynamic lubrication theory reveals relationship between load and friction coefficient and was demonstrated to be helpful to give insight to the lubrication characteristics of journal bearing. The model gave the composition of friction losses, friction coefficient dynamic change with orbiting angle and effect of oil viscosity on compressor performance. The results showed that the friction losses of piston ring/cylinder interface and the rod big end bearing was most part of the friction losses and it was necessary to choose suitable oil viscosity to reach the optimum compressor performance.

An Experimental Analysis of Misalignment Effects on Hydrodynamic Plain Journal Bearing Performances

2001 ◽  
Vol 124 (2) ◽  
pp. 313-319 ◽  
Author(s):  
J. Bouyer ◽  
M. Fillon
Keyword(s):  
Film Thickness ◽  
Journal Bearing ◽  
Hydrodynamic Pressure ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Maximum Pressure ◽  
Minimum Film Thickness ◽  
Oil Flow ◽  
Hydrodynamic Effects

The present study deals with the experimental determination of the performance of a 100 mm diameter plain journal bearing submitted to a misalignment torque. Hydrodynamic pressure and temperature fields in the mid-plane of the bearing, temperatures in two axial directions, oil flow rate, and minimum film thickness, were all measured for various operating conditions and misalignment torques. Tests were carried out for rotational speeds ranging from 1500 to 4000 rpm with a maximum static load of 9000 N and a misalignment torque varying from 0 to 70 N.m. The bearing performances were greatly affected by the misalignment. The maximum pressure in the mid-plane decreased by 20 percent for the largest misalignment torque while the minimum film thickness was reduced by 80 percent. The misalignment caused more significant changes in bearing performance when the rotational speed or load was low. The hydrodynamic effects were then relatively small and the bearing offered less resistance to the misalignment.

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