Transient Analysis of the Textured Journal Bearing Operating With the Piezoviscous and Shear-Thinning Fluids

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Di Zhang ◽  
Youbai Xie
Keyword(s):  
Transient Analysis ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Shear Thinning ◽  
Lubrication Regimes ◽  
Shear Thinning Fluids ◽  
Lubrication Regime ◽  
Start Up ◽  
Metal Metal ◽  
Bearing System

In this paper, a mixed lubrication model is presented to analyze the tribological behavior of the textured journal bearings operating from mixed to hydrodynamic lubrication regimes. In particular, the effects of fluid piezoviscosity and the non-Newtonian fluid behavior are also considered. The presented model solves the hydrodynamic lubrication problem by a mass-conserving formation of the Reynolds equation, whereas the metal–metal contact is considered by using the Greenwood and Tripp (GT) contact model which is linked with the hydrodynamic model based on the concept of Johnson's load sharing. As a result, the performance of the textured journal bearing system under different lubrication regimes, including boundary lubrication regime, mixed hydrodynamic lubrication regime, and hydrodynamic lubrication regime, can be evaluated. Using the journal bearing systems operated under the start-up condition as examples, prediction demonstrates the influences of texture distributions on friction and wear. It is found that the friction reducing effect induced by texturing is influenced by the distribution of the texturing zones. In particular, the hydrodynamic friction can be reduced when the eccentricity ratio is changed from high to low. Moreover, it appears that the shear-thinning effect of lubricant cannot be neglected in the transient analysis of journal bearing system.

Stability Analysis of an Industrial Gas Compressor Supported by Tilting-Pad Bearings Under Different Lubrication Regimes

2011 ◽  
Author(s):  
Alejandro Cerda Varela ◽  
Ilmar Ferreira Santos
Keyword(s):  
Stability Analysis ◽  
Dynamic Behavior ◽  
Journal Bearing ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Stable Operating ◽  
Tilting Pad ◽  
The Stability ◽  
Tilting Pad Journal Bearing ◽  
Bearing System

This work is aimed at theoretically study the dynamic behavior of a rotor-tilting pad journal bearing system under different lubrication regimes, namely thermohydrodynamic (THD), elastohydrodynamic (EHD) and hybrid lubrication regime. The rotor modeled corresponds to an industrial compressor. Special emphasis is put on analyzing the stability map of the rotor when the different lubrication regimes are included into the TPJB modeling. Results show that, for the studied rotor, the inclusion of a THD model is more relevant when compared to an EHD model, as it implies a reduction on the instability onset speed for the rotor. Also, results show the feasibility of extending the stable operating range of the rotor by implementing a hybrid lubrication regime.

Stability Analysis of an Industrial Gas Compressor Supported by Tilting-Pad Bearings Under Different Lubrication Regimes

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Alejandro Cerda Varela ◽  
Ilmar Ferreira Santos
Keyword(s):  
Stability Analysis ◽  
Dynamic Behavior ◽  
Theoretical Study ◽  
Journal Bearing ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Stable Operating ◽  
Tilting Pad ◽  
The Stability ◽  
Tilting Pad Journal Bearing

This work is aimed at a theoretical study of the dynamic behavior of a rotor-tilting pad journal bearing (TPJB) system under different lubrication regimes, namely, thermohydrodynamic (THD), elastohydrodynamic (EHD), and hybrid lubrication regime. The rotor modeled corresponds to an industrial compressor. Special emphasis is put on analyzing the stability map of the rotor when the different lubrication regimes are included into the TPJB modeling. Results show that, for the studied rotor, the inclusion of a THD model is more relevant when compared to an EHD model, as it implies a reduction on the instability onset speed for the rotor. Also, results show the feasibility of extending the stable operating range of the rotor by implementing a hybrid lubrication regime.

The Role of Geometrical Parameters in the Lubrication of the Swiss Lever Escapement

2021 ◽  
Vol 88 (6) ◽  
Author(s):  
Alejandro Roda-Buch ◽  
Valentine A. M. Magnin ◽  
Sandra Guadalupe Maldonado ◽  
Stefano Mischler
Keyword(s):  
Hydrodynamic Lubrication ◽  
Contact Forces ◽  
Geometrical Parameters ◽  
Inverse Dynamic ◽  
Technical Parameters ◽  
Lubrication Regimes ◽  
Multibody Model ◽  
Lubrication Regime ◽  
The Coefficient Of Friction

Abstract The lubrication regimes of a contact pair escapement-ruby pallet of a Swiss lever escapement have been investigated combining the theory of fluid lubrication with a well-established kinematic and inverse dynamic multibody model. The kinematic analytical results have been confronted with experimental measurements. The developed model allows to easily obtain, for the three operating phases of the Swiss lever escapement, the relative speed and the contact forces and, by considering a hydrodynamic lubrication regime, the lubricant minimum film thickness and the coefficient of friction. The presented formulation allows to study the influence of crucial technical parameters in the Swiss lever escapement lubrication. The spout radii of curvature have been identified as the optimal parameters to control the lubrication regimes in the pallet/escapement contacts. In that sense, an interesting result is that the lubrication regime moves away from the boundary lubrication by increasing these radii.

Investigation of the wear of engine journal bearings approaching severe lubrication conditions using a microabrasion tester

2019 ◽  
Vol 233 (12) ◽  
pp. 1939-1949 ◽  
Author(s):  
Andys Hernández-Peña ◽  
Leonardo I Farfan-Cabrera ◽  
Ezequiel A Gallardo-Hernández
Keyword(s):  
Boundary Lubrication ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Mineral Oil ◽  
Constant Load ◽  
Journal Bearings ◽  
Engine Operation ◽  
Lubrication Regimes ◽  
Actual Use ◽  
Steel Balls

Ideally, engine journal bearings are expected to operate under hydrodynamic lubrication regime to limit wear and promote minimal friction by sliding. Nevertheless, engine journal bearings fail since wear caused by severe conditions in actual engine operation, such as start/stop, misalignment, lubricant degradation, overheating, and debris contamination, producing a transition from hydrodynamic to mixed and boundary lubrication regimes and wear increased in both engine journal bearings and crankshaft. Thus, this work aims to study the influence of boundary lubrication, engine mineral oil aging, and debris contamination on wear of engine journal bearings. An adapted microscale abrasion tester using a ball-on-concave flat configuration was used to reproduce boundary lubrication under controlled conditions. Steel balls having a similar surface than crankshafts and concave flat samples cut from actual engine journal bearings were tested. The tests were run under boundary lubrication at a constant load, speed, and sliding distance at 26 ℃ and 100 ℃ using separately clean fresh and aged engine mineral oil, and then, tests were conducted using the oils contaminated with hard abrasive particles. The engine mineral oil was degraded by a laboratory aging process approaching oxidation of an engine mineral oil used in actual use conditions. Oxidation, additives depletion and changes in viscosity were evaluated. The wear volumes and scar morphologies of engine journal bearing samples were analyzed. The results suggested that high temperature was the main contributor for wear increase in engine journal bearings, while oil aging and debris did not influence considerably on the wear. However, the oils contaminated with hard particles produced a wear decrease in engine journal bearing samples but increased wear in rotary balls.

Design and Development of Permanent Magneto-Hydrodynamic Hybrid Journal Bearing

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
K. P. Lijesh ◽  
Harish Hirani
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Magnetic Bearing ◽  
Operating Conditions ◽  
Fluid Film ◽  
Test Setup ◽  
Fluid Film Bearings ◽  
Lubrication Regime ◽  
Load Carrying ◽  
Hybrid Bearing

Fluid film bearings (FFBs) provide economic wear-free performance when operating in hydrodynamic lubrication regime. In all other operating conditions, except hydrostatic regime, these bearings are subjected to wear. To get wear-free performance even in those conditions, a hybrid (hydrodynamic + rotation magnetized direction (RMD) configured magnetic) bearing has been proposed. The hybrid bearing consists of square magnets to repel the shaft away from the bearing bore. Load-carrying capacities of four configurations of hybrid bearings were determined. The results are presented in this paper. The best configuration of hybrid bearing was developed. A test setup was developed to perform the experiments on the fluid film and hybrid bearings. The wear results of both the bearings under same operating conditions are presented.

Research on shaft strength considering offsetting distribution of film pressure of journal bearing in shaft-bearing system

2007 ◽  
Vol 221 (1) ◽  
pp. 99-107 ◽  
Author(s):  
S Jun ◽  
G Changlin ◽  
W Jingfeng
Keyword(s):  
Stress Distribution ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Direct Interaction ◽  
Present Calculation ◽  
Design Calculation ◽  
Film Pressure ◽  
Lubrication Characteristics ◽  
Strength And Stiffness ◽  
Bearing System

There is a direct interaction between shaft and bearing in shaft-bearing system. The effect of lubrication status of bearing was not considered in the present calculation of shaft strength. In this paper, shaft-bearing system was taken as the study object. Hydrodynamic lubrication characteristics of a journal bearing considering misalignment caused by shaft deformation in shaft-bearing system were analysed. There are obvious offsetting distribution of film pressure and increase of the highest film pressure when journal misalignment takes place. Based on the lubrication analysis of bearing, the stress distribution of shaft was calculated when the film pressure calculated was used as boundary condition of load. The results show that there are obvious changes of stress distribution and great increase of stress near the area on shaft where it is acted upon the highest film pressure when considering the offsetting distribution of film pressure. The shaft strength is affected remarkably. Therefore, in order to accord with the tendency today for high precision in the design calculation, thus more reasonable design can be acquired, the coupling between the analysis of bearing tribology and the analysis of strength and stiffness of shaft must be studied in the design of shaft-bearing system.

Non-Linear Unstability Model and Analysis of the Engine Main Journal Bearing

2012 ◽  
Vol 246-247 ◽  
pp. 790-794
Author(s):  
Kang Shao ◽  
Chang Wen Liu ◽  
Feng Rong Bi ◽  
Xia Wang ◽  
Jian Zhang
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Main Bearing ◽  
Linear Effect ◽  
Non Linear ◽  
The Finite Difference Method ◽  
Engine Crankshaft ◽  
Bearing System ◽  
Oil Film Pressure

On the base of Reynolds equation, the dynamic load of an engine crankshaft main journal bearing system is studied. The oil film pressure is solved from the non-Newtonian Reynolds equation with non-linear model of a finite length journal bearing. The flexible crankshaft is coupling with hydrodynamic lubrication of bearing film. The elastohydrodynamic bearing is treated as non-linear bearing with the finite difference method when considered the unstability load that was acted on the main journal. This paper aims to identify the non-linear effect of engine main bearing in the case of unstability load.

A transient analysis of the textured journal bearing considering micro and macro cavitation during an engine cycle

2017 ◽  
Vol 231 (10) ◽  
pp. 1289-1306 ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Di Zhang ◽  
Youbai Xie
Keyword(s):  
Transient Analysis ◽  
Engine Speed ◽  
Statistical Approach ◽  
Journal Bearing ◽  
Operating Conditions ◽  
Deterministic Approach ◽  
Textured Surfaces ◽  
Potential Reduction ◽  
System A ◽  
Bearing System

This paper presents a transient analysis of the textured journal bearing system. A mass-conserving model is developed to consider the combined effects of the inter-asperity cavitation and the macroscopic cavitation between two rough textured surfaces. In this model, the inter-asperity cavitation induced by the roughness is considered by the statistical approach (the classic flow factor methodology), while the deterministic approach is used to deal with the macroscopic cavitation induced by textures and macroscopic geometry. Moreover, the system of discretized equations for this model is unconstrained by reformulating the cavitation conditions, which is in favor of improving the computational efficiency. Furthermore, based on the fully dynamic analysis, the present study examines the effect of different textures (dimple and groove) under the engine operating conditions. It is found that the position of journal center is changed according to the engine speed and then influences the potential reduction effects produced by texturing.

A journal bearing performance prediction method utilizing a machine learning technique

2021 ◽  
pp. 135065012110557
Author(s):  
Georgios N Rossopoulos ◽  
Christos I Papadopoulos
Keyword(s):  
Machine Learning ◽  
Journal Bearing ◽  
Predictive Analytics ◽  
Hydrodynamic Lubrication ◽  
Learning Algorithms ◽  
Machine Learning Algorithms ◽  
Maximum Pressure ◽  
Classification Problems ◽  
Lubrication Regime ◽  
Lift Off

A predictive analytics methodology is presented, utilizing machine learning algorithms to identify the performance state of marine journal bearings in terms of maximum pressure, minimum film thickness, Sommerfeld number, load and shaft speed. A dataset of different bearing operation states has been generated by solving numerically the Reynolds equation in the hydrodynamic lubrication regime, for steady-state loading conditions and assuming isothermal and isoviscous lubricant flow. The shaft has been modelled with four different values of misalignment angle, lying within the acceptable operating range, as defined in the existing regulatory framework. The journal bearing was modelled parametrically using generic geometric parameters of a marine stern tube bearing. The lift-off speed was estimated for each loading scenario to ensure operation in the hydrodynamic lubrication regime and the effect of shaft misalignment on lift-off speed has been evaluated. The generated dataset was utilised for training, testing and validation of several machine learning algorithms, as well as feature selection analysis, in order to solve several classification problems and identify the various bearing operational states.

A New Approach to Determine Lubrication Regimes of Piston-Ring Assemblies

1997 ◽  
Vol 119 (4) ◽  
pp. 808-816 ◽  
Author(s):  
Naeim A. Henein ◽  
Shengqiang Huang ◽  
Walter Bryzik
Keyword(s):  
Piston Ring ◽  
Hydrodynamic Lubrication ◽  
Mixed Lubrication ◽  
Spark Ignition Engine ◽  
Frictional Torque ◽  
New Approach ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Mixed Lubrication Regime ◽  
And Shifts

A new approach is developed to determine piston-ring assembly lubrication regimes from the instantaneous frictional torque measured for the whole engine. This is based on the variation of the friction coefficient with the duty parameter in the Stribeck diagram over the mixed and hydrodynamic lubrication regimes. The derived equation determines the lubrication regimes from the slope of the line in the Stribeck diagram. A single cylinder spark ignition engine was instrumented to determine the total instantaneous frictional torque of the engine. Experiments were conducted under different loads at a constant speed. Results show that the regime is mixed lubrication near the top dead center (TDC) and shifts to the hydrodynamic lubrication regime as the piston moves away from TDC. The extent of the mixed lubrication regime depends on engine load and speed.

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