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1

Research on Hydrodynamic Peek Journal Bearings Lubricated with Water and Oil

Żochowski Tomasz, Olszewski Artur, Wasilczuk Michał

Tribologia

|

2023

|

nr 1

109--115

EN

The main purpose of the research was to determine the possibilities and experimentally test the benefits of replacing conventional oil lubrication with ecological water lubrication. Tests were carried out on a test rig for hydrodynamic radial bearings under conditions representative of the expected applications for the bearing in water turbines. Bearings made from the polymer material PEEK (polyether ether ketone) were tested under static loads. The tests were carried out for two types of lubrication: pure water and oil, with a viscosity of ISO VG 46. A comparison of friction coefficients and load-carrying capacity for both lubricants was made. During the tests, an interesting phenomenon of polymer material running in was observed for relatively high pressures when lubricated with a very low-viscosity lubricating medium, i.e., water (pressures in the bearing over 2 MPa).

PL

Głównym celem badań było określenie możliwości i doświadczalne sprawdzenie korzyści płynących z zastąpienia konwencjonalnego smarowania olejowego ekologicznym smarowaniem wodnym. Przeprowadzono testy na stanowisku badawczym do hydrodynamicznych łożysk poprzecznych w warunkach odpowiadających oczekiwanym zastosowaniom łożyska w turbinach wodnych – prędkość ślizgania około 3 m/s i średnie naciski przekraczające 2 MPa. Łożyska wykonane z materiału polimerowego PEEK (Polieteroeteroketon) były badane w warunkach obciążeń statycznych. Testy zostały przeprowadzone dla dwóch rodzajów smarowania: czystą wodą oraz olejem o lepkości ISO VG 46. Dokonano porównania współczynników tarcia oraz obciążalności dla różnych mediów smarujących. Podczas badań zaobserwowano bardzo wyraźnie przejście od tarcia płynnego to tarcia mieszanego przy naciskach średnich około 0,65 MPa oraz interesujący efekt docierania się materiału polimerowego dla stosunkowo wysokich nacisków przy smarowaniu wodą (naciski w łożysku ponad 2 MPa) polegający na tym, że współczynnik tarcia w dotartym łożysku był niemal niezależny od obciążenia.

2

Elastohydrodynamic analysis of a journal bearing with different grade oils considering thermal and cavitation effects using CFD-FSI

Kadhim Zainab H., Hammed Lekaa, Rahima Fatima A., Ridha Ali Mohammed

Diagnostyka

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2023

|

Vol. 24, No. 2

art. no. 2023213

EN

This paper investigates a three-dimensional CFD analysis of hydrodynamic journal bearing performance for two different available types of lubricants, SEA 10W50 and SEA 15W40, considering thermal, elastic deformation, and cavitation effects. A 3-dimensional CFD model founded on continuity, momentum, energy, in addition elasticity equations has been implemented. The analysis is performed for a bearing with different journal speeds (1000-3000rpm) and eccentricity ratios (0.1-0.9). The cavitation effect was considered using the model of Zwart-Gerber-Balamri multiphase flow model. The bearing material elastic deformation was considered by implementing the two-way FSI technique through ANSYS-FLUENT 2019 R2. A comparative study of the oil film temperature, thermal pressure, also the load capacity by the bearing has been performed. By comparing the current work's oil film temperature results with those obtained by Ferron et al (1983), with a maximum deviation between the results not exceeding 3 percent, the mathematical model was validated. The findings demonstrate that, once the cavitation consequence is taken into account, the lubricant film pressure decreases. Furthermore, at what time the bearing rotates at greater eccentricity ratios and rotational speeds, more deformation material of the bearing is seen. The current research may help in predicting the bearing performance parameters in real-world situations.

3

Design of the turbocharger bearing arrangement to increase the overall efficiency of the combustion engine

Sroka Zbigniew, Prakash Srinath, Włostowski Radoslaw

Combustion Engines

|

2022

|

R. 61, nr 1

83--89

EN

The main objective of this study was to design a journal bearing, such that it can withstand the forces that arise in context to increasing the length of the shaft in an automotive turbocharger. The work will also provide information on how the design changes affect the overall performance of the bearing. The design changes include the thickness of the oil film, the number of grooves, the dimension of the grooves, the number of inlets and outlets, the dimension of the babbitt and mainly the length of the journal bearing. The simulation models were created using CATIA V5 and the analysis is done using ANSYS 19.2. The flow is considered to be laminar and is calculated using Reynold’s Equation. The new concept gave insight on how the design considerations affect the pressure distribution and the pressure developed. From the results, it was interpreted that the new design can withstand the four times the pressure while distributing the pressure over twice the original design.

4

Effect of lubricant compressibility and variable viscosity on the performance of three-lobe journal bearing

Mahdi Mushrek A., Abass Basim Ajeel

Archive of Mechanical Engineering

|

2022

|

LXIX, nr 2

203–-219

EN

Different configurations of journal bearings have been extensively used in turbo- machinery and power generating equipment. Three-lobe bearing is used due to its lower film temperature and stable operation. In this study, static performance of such a bearing has been investigated at different eccentricity ratios considering lubricant compressibility and variable viscosity. The effect of variable viscosity was considered by taking the viscosity as a function of the oil film thickness while Dowson model is used to consider the effect of lubricant compressibility. The effect of such parameters was considered to compute the oil film pressure, load-carrying capacity, attitude an- gle and oil side leakage for a bearing working at (ε from 0.6 to 0.8) and (viscosity coefficient from 0 to 1). The mathematical model as well as the computer program prepared to solve the governing equations were validated by comparing the pressure distribution obtained in the present work with that obtained by EL-Said et al. A good agreement between the results has been observed with maximum deviation of 3%. The obtained results indicate a decrease in oil film pressure and load-carrying capacity with the higher values of viscosity coefficient while the oil compressibility has a little effect on such parameters.

5

Static properties of plain journal bearing

Mazurkow Aleksander, Kalina Adam

Physics for Economy

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2021

|

Vol. 4

41-52

EN

To guarantee a proper operation of a bearing it is necessary that parameters characterizing it in conditions of the start-up phase, a steady state, and run-down phase are known. In the article, plain journal bearing models describing the condition before the start of relative motion (ωJ = 0) were presented. The models were formulated on the grounds of both the Hertz theory and the general theory of elasticity. The bearing operation parameters calculated with the use of the Hertz theory and the solid bush model differ significantly. For the steady state, when ωJ = const, operating conditions were determined from equations of the hydrodynamic lubrication theory. Comparative studies indicate that at higher loads, pressures in the journal-bush contact zone may prove to be decisive for proper operation of the bearing, rather than maximum pressures or maximum oil temperatures.

6

Automatic Fault Classification for Journal Bearings Using ANN and DNN

Narendiranath Babu T., Aravind A., Rakesh A., Jahzan M., Rama Prabha D., Ramalinga Viswanathan M.

Archives of Acoustics

|

2018

|

Vol. 43, No. 4

727--738

EN

Journal bearings are the most common type of bearings in which a shaft freely rotates in a metallic sleeve. They find a lot of applications in industry, especially where extremely high loads are involved. Proper analysis of the various bearing faults and predicting the modes of failure beforehand are Essentials to increase the working life of the bearing. In the current study, the vibration data of a journal Bering in the healthy condition and in five different fault conditions are collected. A feature extraction metod is employed to classify the different fault conditions. Automatic fault classification is performed using artificial neural networks (ANN). As the probability of a correct prediction goes down for a higher number of faults in ANN, the method is made more robust by incorporating deep neural networks (DNN) with the help of autoencoders. Training was done using the scaled conjugate gradient algorithm and the performance was calculated by the cross entropy method. Due to the increased number of hidden layers in DNN, it is possible to achieve a high efficiency of 100% with the feature extraction method.

7

Analysis of hydrodynamic lubrication of journal bearings with oil of non-Newtonian properties

Miszczak A., Sikora G.

Tribologia

|

2017

|

nr 2

127--138

EN

In this paper, the presented issue concerns hydrodynamic lubrication of the journal bearings with the oil of non-Newtonian properties. For the analysis of the hydrodynamic lubrication, a constitutive model of the third order was assumed. The assumed model consist of a Newtonian part –pI+nA1&enspand non-Newtonian part &beta3&ensp tr(A12)A1. The Main part of this paper concerns transformation, nondimensionalization, and an estimation of order of magnitude of the equation, which describes the apparent viscosity. Apparent viscosity describes changes of the dynamic viscosity with shear rate. In this way prepared model of apparent viscosity is used in momentum equations. This equations are integrated in order to designate components of the velocity vector. By substitution of the proper boundary conditions, modified Reynolds type equation is obtained. A further stage of the research will be proceeding of the numerical calculations of the hydrodynamic pressure distribution followed by the designation of the carrying capacity, friction force and friction coefficient while taking changes of the viscosity from shear rate into account (apparent viscosity).

PL

Prezentowana w artykule tematyka dotyczy problemu hydrodynamicznego smarowania poprzecznych łożysk ślizgowych olejem o właściwościach nienewtonowskich. Do analizy hydrodynamicznego smarowania przyjęto część modelu konstytutywnego trzeciego rzędu. Przyjęty model składa się z części opisującej właściwości newtonowskie –pI+nA1&ensporaz części opisującej właściwości nienewtonowskie &beta3&ensp tr(A12)A1. Zasadnicza część pracy dotyczy przekształcenia, ubezwymiarowienia oraz oszacowaniu rzędu wielkości równania opisującego lepkość pozorną, w której uwzględnia się zmiany lepkości dynamicznej od szybkość ścinania. Tak opracowany model lepkości pozornej podstawiany jest do równań pędu i ciągłości strugi. Równania te są całkowane w celu wyznaczenia składowych wektora prędkości. Przy nałożeniu odpowiednich warunków brzegowych uzyskuje się również zmodyfikowane równanie typu Reynoldsa. Dalszym etapem badań będzie wykonanie obliczeń numerycznych rozkładu ciśnienia hydrodynamicznego a następnie wyznaczeniu siły nośnej, siły tarcia i współczynnika tarcia z uwzględnieniem zmian lepkości od szybkości ścinania (lepkości pozornej).

8

Journal Bearing Fault Detection Based on Daubechies Wavelet

Narendiranath B. T., Himamshu H. S., Prabin K. N., Rama P. D., Nishant C.

Archives of Acoustics

|

2017

|

Vol. 42, No. 3

401--414

EN

Journal bearings are widely used to support the shafts in industrial machinery involving heavy loads, such as compressors, turbines and centrifugal pumps. The major problem that could arise in journal bearings is catastrophic failure due to corrosion or erosion and fatigue, which results in economic loss and creates major safety risks. Thus, it is necessary to provide suitable condition monitoring technique to detect and diagnose failures, and achieve cost savings to the industry. Therefore, this paper focuses on fault diagnosis on journal bearing using Debauchies Wavelet-02 (DB-02). Nowadays, wavelet transformation is one of the most popular technique of the time-frequency-transformations. An experimental setup was used to diagnose the faults in the journal bearing. The accelerometer is used to collect vibration data, from the journal bearing in the form of time domain. This was then used as input for a MATLAB code that could plot the time domain signal. This signal was then decomposed based on the wavelet transform. The fast Fourier transform is then used to obtain the frequency domain, which gives us the frequency having the highest amplitude. To diagnose the faults various operating conditions are used in the journal bearing such as Full oil, half loose, half oil, fault 1, fault 2, fault 3 and full loose. Then the Artificial Neural Networks (ANN) is used to classify faults. The network is trained based on data already collected and then it is tested based on random data points. ANN was able to classify the faults with the classification rate of 85.7%. Thus, the test process for unseen vibration data of the trained ANN combined with ideal output target values indicates high success rate for automated bearing fault detection.

9

An analysis of the influence of journal’s helical groove on the wear and load capacity of the sliding bearing

Tomczewski L., Sęp J.

Tribologia

|

2016

|

nr 4

191--199

EN

The article presents the results of a sliding bearing with a helical groove on a journal. The studies included wear tests with contaminated lubrication oil and computer simulation of oil flow based on which the load capa city of a bearing was determined. The 7 bearings with different variants of helical grooves on journal bearings and classical bearings were studied. It was found that the helical groove on the journal makes it possibile to significantly reduce the wear of the bearing in the case of oil contamination with hard particles. It was also shown that the groove on the journal ensures an effective reduction in wear and does not result in a significant reduction of load capacity.

PL

W artykule przedstawiono wyniki badań łożyska ślizgowego ze śrubowym rowkiem na czopie. Przeprowadzone badania obejmowały testy zużyciowe przy smarowaniu olejem zanieczyszczonym oraz komputerową symulację przepływu, na podstawie której wyznaczono nośność łożyska. Przebadano 7 łożyskowań z różnymi wariantami śrubowego rowka na czopie oraz łożysko klasyczne. Stwierdzono, że śrubowy rowek na czopie daje możliwość znacznego zmniejszenia zużycia układu łożyskowego w przypadku zanieczyszczenia oleju twardymi cząstkami. Wykazano również, że rowek na czopie zapewniający efektywne zmniejszenie zużycia nie skutkuje znaczącym zmniejszeniem nośności łożyska.

10

The study of slide bearing properties including the surface texture geometry of a journal

Mazurkow A.

Tribologia

|

2014

|

nr 5

125--133

EN

A static friction during a slide bearing’s start-up appears to be a complicated process. To deal with the phenomenon, the author uses a molecular-mechanical theory of friction. This paper reports the results that show the influence of a surface geometric structure of a journal on a static friction coefficient, a frictional moment and tangential stresses on a bushing surface. In analysis of results, it can be noticed that machining selection and the accuracy of a journal surface have the significant impact on bearing system during its start-up.

PL

Zjawisko tarcia spoczynkowego podczas rozruchu łożysk ślizgowych jest procesem złożonym. Do analizy zjawisk przyjęto molekularno-mechaniczną teorię tarcia. W pracy przedstawiono wyniki badań opisujące wpływ struktury geometrycznej powierzchni czopa na współczynnik tarcia spoczynkowego, moment tarcia i naprężenia styczne na powierzchni panewki. W analizie wyników badań wykazano, że rodzaj i dokładność obróbki powierzchni czopa w istotny sposób wpływa na właściwości węzła łożyskowego podczas jego rozruchu.

11

Method for determination of the static friction factor in slide bearings

Mazurkow A.

Tribologia

|

2013

|

nr 6

47--556

EN

This research work describes a method for the determination of the static friction factor in slide bearings. To determine tangential stresses distribution in a real area of a contact the author uses a molecular-mechanical theory of friction. In this theory, the total frictional force is equal to the sum of system of forces: molecular and material resistance to the deformation of bodies' surface coating. To design a model the following assumptions are accepted: a journal surface is rough, and a bushing surface is perfectly smooth. The results are represented in the form of graph which shows an influence of the contact angle of a journal surface and a bushing on a load, a frictional moment, tangential stresses, and a friction coefficient.

PL

W pracy przedstawiono metodę wyznaczania współczynnika tarcia spoczynkowego w łożyskach ślizgowych. Do określenia rozkładu naprężeń stycznych w rzeczywistym obszarze styku przyjęto molekularno-mechaniczną teorię tarcia. W teorii tej całkowita siła tarcia jest równa sumie sił składowych: molekularnej i odporności materiałów na deformowanie warstwy powierzchniowej ciał. W budowie modelu przyjęto m.in. założenia: powierzchnia czopa jest chropowata, natomiast powierzchnia panewki jest idealnie gładka. Wyniki obliczeń, wpływ kąta kontaktu powierzchni czopa i panewki na obciążenie, moment tarcia, naprężenia styczne, współczynnik tarcia przedstawiono w formie wykresów.

12

Badanie zużycia panewki w poprzecznym łożysku ślizgowym

Michalak R., Wójcicki R.

Autobusy : technika, eksploatacja, systemy transportowe

|

2013

|

R. 14, nr 3

645-654

PL

W artykule przedstawiono metodę, która pozwala wyznaczyć profil zużycia panewki łożyska ślizgowego. Metoda ta polega na określeniu zarysu okrągłości powierzchni roboczej łożyska ślizgowego. Profil zużycia panewki ustalono wyznaczając położenie łuku zużycia oraz lokalnych zmian promienia panewki na łuku zużycia. W artykule przedstawiono przykłady zużycia panewek po różnych okresach eksploatacji dla dwóch stopów łożyskowych.

EN

This paper presents the method that allows determining of the wear of operating surface of radial bearing sleeve. The wear measurement consists in determination of the roundness profile deviation of sleeve internal diameter. The developed method allows determining of wear profile by means of its orientation, the length of wear arc as well as the local variation of sleeve radius on the wear arc. The examples of sleeve wear after different periods of exploitation wear presented, too.

13

The effect of helical groove geometry on journal abrasive wear

Sep J., Pawlus P., Galda L.

Archives of Civil and Mechanical Engineering

|

2013

|

Vol. 13, no. 2

150--157

EN

The article presents an experimental study of slide bearings operating in lubricant contaminated by Al2O3 abrasive particles. The aim of this work was the comparison of wear resistance of slide bearings with different surface geometry on the journal. It was found that helical groove on the journal significantly reduced wear of sliding pairs. The results of experiments showed that groove cross section area and helical groove lead affected abrasive wear. Valuable results concerning the sleeve wear reduction were obtained with respect to bearings with textured journals.

14

Possibilities of sliding bearings properties modification by non-typical journal application

Sep J.

Archives of Civil and Mechanical Engineering

|

2013

|

Vol. 13, no. 2

168--174

EN

The article presents the results of investigations into the wear of slide bearings with a non-typical bearing journal. Pairs made up of elements of different hardness operating together and journals of different design were studied. The possibility of reducing the wear due to contaminant hard particles in the oil by a change in the journal design was pointed out. The reduced material loss in this situation is probably due to contaminants being effectively removed from the abrasive contact area owing to the belts of soft material and the grooves on the surface of the journal. It was also found that the modified journal reduces wear in concentrated linear contact. This is probably due to effective, wear reducing boundary layers which form during friction owing to the presence of a modifying material.

15

Bexperimental Investigation into Tribopairs Journal Sleeve of Journal Bearing

Michalak R., Wójcicki R.

Machine Dynamics Research

|

2012

|

Vol. 36, No. 3

53-64

EN

This paper presents the results of plain journal bearings with the operating surface covered by white metal bearing alloys: tin and lead operating with steel journal and bush poured by bronze and nitrosulfonized. It also presents preliminary studies of bearing set: hardened steel journal covered with a layer of nano-composite nc-WC/aC: H - bush of bearing metal as lead alloy. The effect of wear on the tribological characteristics of the bearing was investigated. During the tests a continuous identification of friction conditions was monitored in the bearing. The wear was determined by a method based on the measurement of the roundness of bearing operating surface as well as on the traditional way by weight.

16

Zużycie łożyskowań ślizgowych ze zmodyfikowaną konstrukcją czopa w przypadku zanieczyszczenia oleju cząstkami ściernymi

Sęp J.

Tribologia

|

2011

|

nr 6

201-209

PL

W artykule przedstawiono wyniki badań zużycia łożyskowań ślizgowych smarowanych olejem zanieczyszczonym tlenkiem glinu. Przebadano sześć skojarzeń różniących się twardością współpracujących elementów oraz konstrukcją czopa. Wykazano możliwość zmniejszenia zużycia wywołanego zawartymi w oleju twardymi zanieczyszczeniami poprzez zmianę konstrukcji czopa. Przeprowadzono ponadto analizę porównawczą intensywności zużycia dla testowanych skojarzeń ślizgowych.

EN

Results of tribological wear investigations concerning sliding bearings with six different journals in the presence of an oil abrasive contaminant are presented in the paper. The investigated variants are as follows: – Variant 1 – journal made from C45 steel (hardness 86 HB) mating with sleeve made from MB 50 alloy (79% Al, 20% Sn, 1% Cu, hardness žHV0,1 = 600 MPa), – Variant 2 – journal made from heat-treated 34CrNiMo6 steel (hardness 34 HRC) mating with a sleeve made from MB 50 alloy, – Variant 3 – journal made from heat-treated 34CrNiMo6 steel (hardness 34 HRC) with a two- component surface layer (steel-copper) mating with a sleeve made from MB 50 alloy, – Variant 4 – journal made from heat-treated 34CrNiMo6 steel (hardness 34 HRC) with two- component surface layer (steel-copper) mating with a sleeve made from heat-treated C45 steel (hardness 30 HRC), – Variant 5 – journal made from heat-treated 42CrMo4 steel (hardness 52 HRC) mating with a sleeve made from MB 50 alloy, and – Variant 6 – journal made from heat-treated 42CrMo4 steel (hardness 52 HRC) with a helical groove mating with a sleeve made from MB 50 alloy. The lubricating agent was SAE 40 oil contaminated with Al2O3 particles. Wear volumetric intensity (Iv) for all investigated bearings, as a quotient of volumetric wear and friction path, was calculated. The least tribological wear (Iv = 0.85 mm3/km) was stated for Variant 4. The research indicates that both of the investigated journal modifications resulted in a wear intensity decrease (for variant 3 Iv = 2.73 mm3/km, for variant 6 Iv = 1.21 mm3/km) in the case of an abrasive contaminant in the oil.

17

Surface topography of slide journal bearings

Miszczak A., Czaban A.

Journal of KONES

|

2011

|

Vol. 18, No. 3

279-285

EN

In this article the measurements results of surface topography of different types of slide bearings sleeves have been presented. The research has been conducted with the use of atomic force microscope (AFM). The results of measurements of surface topography were presented in the form of surface topography maps, three-dimensional graphs and some examples of selected cross-sections of investigated surface in the form of profile graphs. Measurements of surface topography were made for thin-walled sleeves of slide journal bearings covered with PTFE, POM, bronze and white metal layers. Operated and new sleeves have been considered with the use of Atomic Force Microscope NT-206produced in MTM in Minsk, Republic of Belarus [2]. Atomic Force Microscope NT-206 provides information for samples with maximum roughness value plus or minus 1 mi m. Max. field in one scanning process is up to 32)um x 32mi m. Measurements were preceded with resolution 256x256points. Presented in the work results of surface topography measurements also include the calculated values of average deviation profile Ra and Rq and the value of fixed distance between the lowest and highest inequality. The application SurfaceXplorer was used for processing and visualization of the data obtained from AFM NT-206, which besides from generating 2D, 3D and profile diagrams, was used to calculate and draw graph of height distribution. The comparison of received data will allow verifying type and amount of surface wear of discussed journal micro-bearings parts in micro and nanoscale and will help to design surface layers with improved tribological properties.

18

Pressure and velocity distribution in slide journal bearing lubricated micropolar oil

Krasowski P.

Journal of KONES

|

2011

|

Vol. 18, No. 4

213-220

EN

Present paper shows the results of numerical solution Reynolds equation for laminar, steady oil flow in slide bearing gap. Lubrication oil is fluid with micropolar structure. Materials engineering and tribology development helps to introduce oils with the compound structure (together with micropolar structure) as a lubricating factors. Properties of oil lubrication as of liquid with micropolar structure in comparison with Newtonian liquid, characterized are in respect of dynamic viscosity additionally dynamic couple viscosity and three dynamic rotation viscosity. Under regard of build structural element of liquid characterized is additionally microinertia coefficient. In modelling properties and structures of micropolar liquid one introduced dimensionless parameter with in terminal chance conversion micropolar liquid to Newtonian liquid. The results shown on diagrams of hydrodynamic pressure, velocity and velocity of microrotation distribution in dimensionless form in dependence on coupling number N2 and characteristic dimensionless length of micropolar fluid A1. Differences were showed on graphs in the schedule of the circumferential velocity oils after the height of the gap in the flow of the micropolar and Newtonian liquid. In presented flow, the influence of lubricating fluid inertia force and the external elementary body force field were omitted. Presented calculations are limited to isothermal models of bearing with infinite length.

19

Wpływ geometrii szczeliny smarowej na nośność łożyska z czopem ze śrubowym rowkiem

Sęp J.

Tribologia

|

2010

|

nr 5

235-244

PL

Celem zaprezentowanych w artykule analiz było określenie wpływu śrubowego rowka na czopie na nośność poprzecznego łożyska ślizgowego. W efekcie przeprowadzonych badań zaproponowano dwa wskaźniki, za pomocą których można dokonać prognozy wpływu geometrii rowka i szczeliny smarowej na nośność. Artykuł zawiera również zestawienie wartości wskaźników oraz nośności wyznaczonych dla konkretnych przykładów łożysk.

EN

Investigations concerning the influence of a helical groove on the load carrying capacity of hydrodynamic plain bearing are presented in the paper. Two indicators were developed as a result of investigations. The first indicator is a quotient of groove volume and bearing interspace volume. It has been stated that, if the value of this indicator does not exceed 0.5% the load carrying capacity of the grooved bearing is above 90% that of classical bearing. The second indicator is a quotient of the groove’s cross-section area and bearing interspace cross-section area in the place of minimum bearing interspace thickness. It has been stated, that if the value of this indicator does nott exceed 2% load carrying capacity, the decrease in load capacity of the grooved bearing is less than 10% in relation to a bearing with smooth journal. The above mentioned dependencies are initial and should be studied in additional investigations.

20

Pressure and velocity distribution in slide journal bearing lubricated micropolar oil

Krasowski P.

Journal of Polish CIMAC

|

2010

|

Vol. 5, no 1

119-126

EN

This paper shows results of numerical solutions an modified Reynolds equations for laminar unsteady oil flow in slide journal bearing gap. Laminar unsteady oil flow is performed during periodic and unperiodic perturbations of bearing load or is caused by the changes of gap height in time. During modelling crossbar bearing operations in combustion engines, bearing movement perturbations from engine vertical vibrations causes velocity flow perturbations of lubricating oil on the shaft in the circumferential direction. This solution example apply to isothermal bearing model with infinity length. Lubricating oil used in this model has Newtonian properties and constant dynamic viscosity. Results are presented in the dimensionless hydrodynamic pressure and tangential tension distribution diagrams. Diagrams also presents capacity and friction force change during the time of velocity perturbations. Received solutions were compared with the solution received by the stationary lubrication flow in the slide journal bearing, which were made with the same parameter assumption by constant dynamic oil viscosity. Isothermal bearing model is similar to friction node model by steady-state heat load conditions. Described effect can be used as on example of modeling the bearing friction node operations in reciprocating movement during exploitation of engines and machines.