Michel Fillon

Michel Fillon
Institut Pprime | Institut P’ · Génie Mécanique et Systèmes Complexes

PhD, HDR
Formerly CNRS Director of Research, Pprime Institute, University of Poitiers, France. Retired on 1st January 2022

About

217
Publications
52,775
Reads
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4,309
Citations
Additional affiliations
January 2010 - present
French National Centre for Scientific Research
Position
  • CNRS Director of Research
October 1999 - December 2009
Université de Poitiers
Position
  • CNRS Research Director
May 1988 - September 1999
Université de Poitiers
Position
  • CNRS Researcher

Publications

Publications (217)
Article
The novelty of this paper is to explore the role of the imperfect journal, including the amplitude and waviness of journal error, on the tribo-dynamic behaviors of the water-lubricated bearing during start-up. To characterize the lubrication performance more practically, the elastic-plastic asperity contact behavior during start-up is considered in...
Article
The article presents selected characteristics of journal bearings calculated with the use of various methods and compared to the results obtained with application of the basic bearing characteristics calculation procedure, as described in the ISO 7902:2020 standard. Additionally, the presented calculation results were compared with the parameters m...
Article
Despite numerous experimental and theoretical studies reported in literature, surface micro-texturing to control friction and wear in lubricated tribo-contacts is still in the trial-and-error phase. The tribological behaviour and advantageous micro-texture geometries and arrangements largely depend on the contact type and the operating conditions....
Article
A thermohydrodynamic model was used to study the influence of partial composite coatings on the behavior of plain journal bearings, considering solid elastic deformations and wall slip occurring at the oil film–polytetrafluoroethylene coating interface, and heat conduction between film, coating, interlayer and basement. The purpose is to design par...
Article
The aim of the study is to investigate the performance of a thrust bearing equipped with hydrostatic lift pockets under different lubrication modes. Three types of flat land bearing lubrication modes are studied experimentally: hydrostatic lubrication (HS; forced oil injection to the pockets), hybrid lubrication (HS + HD; hydrostatic lubrication co...
Article
The aim of the study is to investigate the performance of a thrust bearing equipped with hydrostatic lift pockets under different lubrication modes. Three types of flat land bearing lubrication modes are studied experimentally: hydrostatic lubrication (HS; forced oil injection to the pockets), hybrid lubrication (HS+HD; hydrostatic lubrication comb...
Article
Full-text available
The lifespan of journal bearings is directly related to the operating conditions they have to face and reducing their maintenance intervals allows one to have a clear idea about their performance when issues occur. The presence of scratches on one of its surfaces degrades the performance of a journal bearing. These effects have already been assesse...
Article
Energy production machinery is one of the main subjects of current engineering research. Manufacturers and users are seeking to increase the performance of these machines and, thus, to extend the maintenance intervals as far as possible. It is therefore essential to predict their behavior according to their wear to schedule maintenance operations....
Article
Fluid film thrust bearings are commonly used in industry, providing durable and reliable operation at high values of load carrying capacity, accompanied by low friction losses. A major advantage of hydrodynamic fluid film bearings, over other types of bearings, is their enhanced dynamic behaviour, especially under transient or impact loads. Current...
Article
A performance optimisation study of a thrust bearing with surface texturing has been addressed. Bearing response calculations have been performed with a thermohydrodynamic modelling approach. A THD-optimal bearing design has been calculated, and a sensitivity analysis has been performed. The optimal design has been evaluated utilising a thermoelast...
Article
In present work, in order to optimize partial slip zone for heavily loaded journal bearings, an isothermal hydrodynamic model considering wall slip occurring at oil-bush interface is built. Two-component slip model is utilized to calculate slip velocity. The performances of the journal bearing in different slip zone shapes and eccentricity ratios a...
Article
In the present work, a CFD numerical investigation of the tribological characteristics of parallel and quasi-parallel slider bearings has been performed. The work is initiated following experimental observations of load carrying capacity on parallel thrust bearings. The computational results conclude that the principal mechanism of pressure build-u...
Article
Using the experience acquired within our lab in terms of both thermohydrodynamic (THD) and thermoelastohydrodynamic (TEHD) numerical simulations, a new THD code has been improved by adding the possibility of taking into account geometrical defects, and particularly scratches, which are often discovered by turbine users during maintenance operations...
Article
The effect of surface roughness on the transient characteristics of the hydrodynamic cylindrical bearing during startup is studied. A mixed lubrication model considering both asperity contact and hydrodynamic fluid flow is solved. The asperity contact pressure is obtained by the Greenwood-Williamson (GW) contact model. The hydrodynamic pressure is...
Article
Full-text available
During the start-up period, if the journals bearing bushing and shaft materials have different heat conductivities, the thermal expansion of the shaft might be more rapid than that of the bushing. This reduces the radial clearance between the bearing components and generates higher shear stresses in the lubricating fluid, which can lead to bearing...
Article
Most of the investigations on thrust bearings were performed under a steady-state condition and this regime is now well understood. Contrary to this, the behavior during the first period of start-up is sparsely studied. Start-ups of thrust bearings are critical periods where a mixed lubrication regime occurs. This regime can be detrimental for the...
Presentation
Full-text available
[Link to Extended Abstract: http://www.ibertrib-2017.dem.uminho.pt/PDFs/61-CO.pdf] Hydrodynamic journal bearings have been long used in rotating machinery for the support of high speed/highly loaded shafts. Their design procedure has evolved over the years, often involving a combination of numerical simulations and empirical data. Recent trends in...
Article
Full-text available
This study investigates the evolution of the main bearing performance of partially and fully textured hydrodynamic journal bearing. The viscosity effect is also analysed by the mean of numerical simulations for two types of oil: the oil 1 (ISO VG 32, 31.3 cSt at 40 °C) has a lower viscosity than oil 2 (ISO VG 100, 93 cSt at 40 °C). Reynolds equatio...
Article
During maintenance operations of steam turbines, one often found issue is the degradation of the supporting and guiding components for the rotating shafts due to the presence of scratches. To examine this issue, a numerical software program has been developed. In order to validate and to complete the elaborated modeling, experimental tests have bee...
Article
Full-text available
Multi-axial groove hydrodynamic journal bearings are often preferred over single grooved ones to improve lubricant distribution. However, when assessing the influence of loading angle for a twin axial groove bearing, the authors detected the occurrence of phenomena such as strong negative flow rate in one of the grooves for a broad range of loading...
Article
The fluid film pressure and temperature fields have been measured simultaneously under laboratory conditions at one land of a Circumferential Groove Journal Bearing (CGJB), together with friction torque and oil flow rate, during a time span from stand-still start-up to the development of a thermally stabilized steady operating regime. A very fine m...
Conference Paper
This study investigates the evolution of the main bearing performance of partially and fully textured hydrodynamic journal bearing. The viscosity effect is also analysed by the mean of numerical simulations for two types of oil: the oil 1 (ISO VG 32, 31.3 cSt at 40 °C) has a lower viscosity than oil 2 (ISO VG 100, 93 cSt at 40 °C). Reynolds equatio...
Conference Paper
This work compares the viscosity effect of two different oils used as lubricant in a textured hydrodynamic journal bearing. The textured bearing performance enhancement passes by a minimum film thickness and a friction torque improvement through an appropriate surface texturing. The used numerical approach in this analysis is finite difference meth...
Article
Full-text available
Hydrostatic assistance is a commonly used method to improve limited load carrying ability of tiltingpad thrust bearings during transient states of operation of vertical shaft hydro-generators. Despite of special hydraulic equipment (as pumps, valves, etc.), it also requires manufacturing of special recesses/pockets at pad sliding surfaces, into whi...
Conference Paper
Simultaneous measurements of the fluid film pressure and temperature fields have been performed during the start-up regime for a lightly loaded two-land symmetrical circumferential groove journal bearing (specific pressure: 0.25 MPa; diameter: 100 mm; acceleration and nominal speed: 0 to 4000 rpm in 20 s). The measurements grid consists in 4 axial...
Article
Full-text available
Textured surfaces are the subject of a great deal of research work in tribology, which mainly involves numerical studies of lubricated contacts. A variety of shapes and arrangements of textures can be found, these being as numerous as the different authors. Depending on the configuration, it has been shown that the presence of the texture can provi...
Article
Journal bearing characteristics modellization has been investigated in this paper for both cases of texture presence or absence onto the bearing surface. The thermal effect has been studied. The used numerical approach in this analysis is Finite Difference Method. The textured bearing performance enhancement passes essentially by a minimum film thi...
Article
The journals bearing characteristics with texture presence on the bearing surface are investigated. The thermal effect has been studied. The used numerical approach in this analysis is Finite Difference Method. The textured bearing performance enhancement passes essentially by a minimum film thickness and a friction torque improvement through an a...
Article
Full-text available
The journal bearing is a complex system with high film convergence and with cavitation hydrodynamic phenomena. The surface texturation influence study on journal bearing performances requires unavoidably experimental investigations followed by a numerical modelling of the problem. This work consists in modellization and understanding of the journal...
Article
Full-text available
In this paper, a computational investigation of thermohydrodynamic performance and me-chanical deformations of a fixed-geometry thrust bearing with artificial surface texturing is presented. A parallel eight-pad bearing is considered; the surface of each pad is partially textured with square dimples. Here, a CFD-based thermohydrodynamic modeling ap...
Article
Full-text available
The performance of hydrodynamic journal bearings is affected by the conditions under which the lubricant is fed to the bearing gap. Axial grooves are often used and, depending on their location relatively to the load line, they might substantially interfere with the hydrodynamic pressure generation and the thermal behaviour of the bearing. However,...
Article
Hydrodynamic thrust bearings, used to carry axial loads in heavily loaded shafts of water power plants hydro turbines, can reach outer diameters even exceeding 5 m. In such large objects scale effect could be observed. According to this, allowable bearing specific load assuring safe operation of the bearings has to be decreased, which increases thr...
Article
An experimental study is presented with the main objective of understanding the hydrodynamic behavior of a tapered-land thrust bearing with fixed geometry. The experimental results were obtained using an original test rig designed at the “Institut Pprime.” Extensive instrumentation applied to the thrust bearing allows a precise evaluation of variou...
Article
Full-text available
Most conventionalhydrodynamicjournalbearingperformancetoolscannotsuitablyassesstheeffectof lubricant feedingconditionsonbearingperformance,eventhoughtheseconditionsareknowntoaffect important performanceparameterssuchaseccentricityandpowerloss. A thermohydrodynamicanalysissuitabletodealwithrealisticfeedingconditionshasbeenproposed. Special attention...
Article
Full-text available
Different geometry patterns of the surface of thrust bearings have been proven very beneficial in terms of bearing load carrying capacity and friction coefficient. In this study, four different types of sector-pad thrust bearings have been cross evaluated for operation under realistic operating conditions: (a) an open pocket bearing, (b) a closed p...
Article
Full-text available
The paper presents a detailed computational study of flow patterns and performance indi-ces in a dimpled parallel thrust bearing. The bearing consists of eight pads; the stator surface of each pad is partially textured with rectangular dimples, aiming at maximizing the load carrying capacity. The bearing tribological performance is characterized by...
Article
Full-text available
Recent studies of our group on the behavior of thrust bearings with textured surface have provided numerous experimental data, allowing characterizing the behavior of such devices operating under steady-state and transient (start-up period) regimes [1, 2, 3]. The present work aims to compare the performance of several types of thrust bearings; both...
Article
During the last decade, researchers have paid a great attention to the textured surfaces in many tribological applications such as piston-rings, thrust and journal bearings, thus emphasing the interest of using textured surfaces. Recent studies of our group have provided numerous experimental data on the behavior of thrust bearings with textured su...
Article
Full-text available
Hydrodynamic journal bearing supporting high mass rotating machinery are subjected to low rotational speeds during start-up or idling phases. These working conditions need a hydrostatic pressure contribution to ensure a correct load capacity when the hydrodynamic pressure is not established yet. This is possible by means of hydrostatic lift pockets...
Article
Full-text available
Surface texturing has been shown to reduce friction and increase the film thickness in various tribological applications (hydrodynamic bearings, mechanical seals, and cylinder–liner contacts). However, only few studies discuss optimal texturing properties, and most of them focus on the optimal dimple shape. This article proposes an in-depth study o...
Article
In this work, performance degradation in scratched journal bearings is evaluated by means of numerical simulations. A hydrodynamic numerical model with global thermal effects is employed (lubricant temperature and viscosity are assumed to be uniform). A very fine mesh is used, which allows a deterministic representation of a large number of circumf...
Article
Even if water has more favorable thermal characteristics than oil, its use in the realm of bearings is still restricted to some rare applications. Moreover, the presence of water in lubricating circuits is seen as not at all desirable. The contamination of oil by water results in dangerous effects on lubrication. In relation to this, the study of t...
Conference Paper
Full-text available
The hydrodynamic journal bearing is still one of the most geometrically simple mechanical components, yet highly reliable and efficient and, above all, unique in what concerns to heavy duty – high load, high speed – support of rotating shafts. Analytical studies, not only to understand the physical basis of its performance, but also to develop prac...
Conference Paper
Full-text available
The paper presents a detailed computational study of flow patterns and performance indices in a dimpled parallel thrust bearing. The bearing consists of eight pads; the stator surface of each pad is partially textured with rectangular dimples, aiming at maximizing the load carrying capacity. The bearing tribological performance is characterized by...
Article
Part of the heat generated by the shearing of the lubricating film during operation of a hydrodynamic bearing is transferred to the bearing components. In the case of the pad, which is usually fully submerged in the lubricating oil, heat is further transferred at the pad free walls to the oil by convection. This mechanism causes a thermal gradient...
Article
The effect of water contamination on the lubrication has been described in several studies. Water has been defined as a dangerous contaminant which has a very detrimental impact on bearing performance. Nevertheless, many of the previous studies are based on post-accidental analyses, made after the lubrication failure. Thus, these analyses do not ta...
Article
The paper presents a combined experimental and computational study of tribological parameters of a textured eight-pad parallel thrust bearing. The stator surface of each pad is partially textured with square dimples. A series of experiments at low and moderate thrust loads are conducted, accompanied by detailed CFD simulations which take into accou...
Conference Paper
An experimental study is presented with the main objective of understanding the hydrodynamic behavior of a taper land thrust bearing with fixed geometry. The experimental results were obtained on an original test rig designed at the Pprime Institute. An extensive instrumentation of the thrust bearing allows a precise evaluation of various elements...
Conference Paper
An experimental study is presented with the main objective of understanding the hydrodynamic behavior of a taper land thrust bearing with fixed geometry. The experimental results were obtained on an original test rig designed at the Pprime Institute. An extensive instrumentation of the thrust bearing allows a precise evaluation of various elements...
Article
This article is an experimental and numerical study on elastohydrodynamic behavior of a plain cylindrical journal bearing subjected to the radial loads. An experimental study conducted on the effects of applied load on the determination of the characteristics of a cylindrical journal bearing, with 100 mm diameter and a radial clearance of 0.09 mm....
Conference Paper
Full-text available
This paper describes the phenomenon of negative flow rate (hot oil reflux) occurring in one of the grooves of twin axial groove hydrodynamic journal bearings. This rarely described phenomenon, which can occur under severe operating conditions, increases the risk of bearing seizure. Existing codes for predicting bearing behaviour do not seem to be s...
Conference Paper
The relevance of calculating accurately the oil film temperature build up when modeling tilting-pad journal bearings is well established within the literature on the subject. This work studies the feasibility of using a thermal model for the tilting-pad journal bearing which includes a simplified formulation for inclusion of the heat transfer effec...
Conference Paper
The hydrodynamic thrust bearings are very well-known: their operating characteristics have been the aim of numerous studies, for both numerical and experimental aspects and mainly for the tilting pad configurations. Nevertheless, only few of these studies are devoted to the experimental measurements by considering the materials. The aim of the pres...
Conference Paper
Full-text available
The viscosity of polymer-containing oils decreases at high shear rates; it would follow that reducing viscosity enhances performance by decreasing frictional losses in journal bearing lubrication but impedes performance by increasing metal contact. However, as our previous study confirmed, no such trade-off occurred. It is also considered that the...
Conference Paper
The aim of this study is to present distributions of the film pressure and temperature measured at one land of a two-land Circumferential Groove Journal Bearing (CGJB) during start-up and steady state operating conditions. Simultaneous pressure and temperature measurements are performed in both axial and circumferential directions. Five axial plane...
Article
Full-text available
The improvement of fuel efficiency has been required even for automotive engine oil. Polymers are wideldy to reduce the friction in hydrodynamic lubrication in engines. On the other hand, the regulation of Pb in bearing materials has begun with the goal of preventing heavy metal pollution. In order to analyze the effect of polymers with different k...
Article
A numerical THD model is developed to investigate the effect of lining compliance on the bearing characteristics. The analysis shows increased load carrying capacity, significantly reduced peak pressures and thicker oil film in the loaded zone compared to a white metal bearing. Slightly thinner oil films are predicted at the bearing edges. Temperat...
Conference Paper
Full-text available
Steady-state tests are performed on a 100 mm, in diameter, Circumferential Groove Journal Bearing (CGJB), consisting of two 20 mm lands. The supply groove’s depth is adjustable by mounting special adapters. The lubricant pressure and temperature values are measured in five, respectively four, axial planes in one of the lands with high accuracy tran...
Conference Paper
In the paper, numerical TEHD results for one of the biggest water power plant Itaipu were compared to available measurement data. Numerical simulations were carried out with the use of bearing model for which the accuracy was previously confirmed with the measurements available for smaller bearings. Several cases were analyzed. The only differences...
Conference Paper
Full-text available
A theoretical model for thermally induced seizure, based on a lumped model analysis, has been previously developed by Cristea et al. in 2010 [1]. Due to the increase of the average global temperature, the system encounters clearance loss, which ultimately can lead to seizure. This study presents a series of experiments designed to validate the tran...
Conference Paper
Full-text available
The operating principle of hydrodynamic thrust bearings with flat pad surfaces has always been the focus of scientific debate. The rounded inlet edges, the thermal expansion of the fluid along the pads or the thermal expansion of the bearing material lie at the base of most hypotheses that attempted to explain the load carrying capacity of this typ...