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  • 1.
    Cervantes, Michel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Cupillard, Samuel
    Hydro-Québec Research’s Institute.
    3D thermodynamic analysis of a turbulent textured slider2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Sliding contacts under laminar regime have been extensively investigated under the last years. The results indicate the possibility to increase load carrying capacity in a slider bearing with more than 10%. The effect of dimples on a slider bearing under a turbulent regime has not yet been investigated. It is the object of the present study. The numerical analysis of a 3D textured slider bearing with fore-region and extended channels at the outlet and on the sides of a pad is considered with a temperature dependent fluid, 2 different types of dimple shape and different operating conditions. The simulations are carried out for a turbulent flow (Re=4.4•10^3- 15•10^3) using Detached Eddy Simulation. The results indicate no gain on the load carrying capacity with the dimple shapes (rectangular and oblique) investigated. A higher operating temperature is found in the presence of dimples.

  • 2.
    Cervantes, Michel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Cupillard, Samuel
    Hydro-Québec Research’s Institute.
    Bance, Kevin
    National Institute for Applied Science.
    Kokkolaras, Michael
    McGill University.
    Shape optimization of a 3D slider with dimples2012Inngår i: Journal of Civil Engineering and Architecture, ISSN 1934-7359, E-ISSN 1934-7367, Vol. 6, nr 12, s. 1599-1607Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sliding contacts in laminar flow regimes have been investigated extensively in recent years. The results indicate the possibility to increase load carrying capacity in a slider bearing for more than 10% with the addition of dimples. Parametric studies have been performed to determine optimal size and position, with emphasis in the optimal shape and position of the dimple for an operating condition. In this article, the numerical analysis of a 2D textured slider bearing with a dimple is initially considered with an isothermal laminar fluid. Position, depth, width and convergence ratio are optimized, the results demonstrate the importance of the width and convergence ratio to increase load. Then, the numerical analysis of a 3D textured slider bearing with fore-region and extended channels at the outlet and on the sides of a pad is considered. The simulations are also carried out for a laminar isothermal flow. Three dimples are considered and their depth is optimized.

  • 3.
    Cervantes, Michel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Cupillard, Samuel
    Hydro-Québec Research’s Institute.
    Kokkolaras, Michael
    University of Michigan.
    Shape optimisation of a 3D slider with a dimple2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Sliding contacts under laminar regime have been extensively investigated under the last years. The results indicate the possibility to increase load carrying capacity in a slider bearing with more than 10% with the addition of dimples. Parametric studies have been performed on size and position, while an optimisation to determine the true potential have not yet been examined. Of interest is the optimal shape of the dimple function of the operating condition and position. In the present work, the numerical analysis of a 2D textured slider bearing with fore-region is initially considered with an isothermal laminar fluid. One dimple is considered and the shape optimized for different operating conditions and positions. Then, the numerical analysis of a 3D textured slider bearing with fore-region and extended channels at the outlet and on the sides of a pad is considered with a temper-ature dependent fluid. The simulations are also carried out for a laminar flow. One dimple is considered and the shape optimized for different operating conditions and positions.

  • 4.
    Cupillard, Samuel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Lubrication of conformal contacts with surface texturing2007Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Conformal contacts like those found in journal or inclined slider bearings are widely encountered in various types of machines from small engines to large turbines. These contacts involve convergent gaps that are used to separate the surfaces in relative motion and generate pressure in the lubricant film. The contacts have to carry a load while keeping friction as low as possible. Environmental and economic concerns require the machines to operate with minimal power loss. A number of design modifications have been proposed over the years in order to decrease bearing power consumption. There are indications that surface topography can have a significant and positive influence on hydrodynamic performance. Texturing of a load carrying surface is a process that would be beneficial in lubricated conformal contacts as it would be possible to obtain thicker films and reduced frictional losses. Textured lubricated contacts are analysed with Computational Fluid Dynamics (CFD) code through different geometries. The effects of the texture on hydrodynamic performance of the contact are investigated. For the simulations performed, the full Navier-Stokes equations are solved under steady-state conditions. The flow is taken to be laminar and two- dimensional. A journal bearing with several dimples created on the stationary part is firstly investigated. A realistic multiphase flow cavitation model is introduced and successfully validated. It is shown that the coefficient of friction can be reduced if dimples of suitable depth are introduced. This can be achieved either in the region of maximum hydrodynamic pressure for a bearing with high eccentricity ratio or just downstream of the maximum film for a bearing with low eccentricity ratio. A new effect of pressure build-up, generated by the surface texture, has been identified at low eccentricity ratios. This pressure build-up effect is more extensively investigated through the study of an inclined slider bearing with a texture located at the inlet part of the contact, i.e. just downstream of the maximum film. The governing mechanism at the origin of an optimum in load carrying capacity for a smooth slider bearing is analysed and the effects of the texture on the pressure build-up and load carrying capacity are explained. The energy received by the fluid from the moving wall is converted into pressure in the first part of the converging contact and into losses in the second part. Convergence ratio can be increased until the limit where flow recirculation begins to occur is reached in order to get the greatest pressure gradient. The texture appears to reach its maximum efficiency when its depth is such that the velocity profile is stretched at its maximum without incoming recirculating flow. Thus, the wall profile shape controlling the velocity profile can be optimized for many hydrodynamic contacts. For such contacts, heat is usually produced due to shearing of the flow and the lubricant is subjected to temperature variations. Since the dynamic viscosity of the lubricant is temperature dependent, variation of the viscosity as well as frictional losses and load carrying capacity is expected. Thermal effects are analysed for different shear rates in this inlet textured slider bearing. Shear losses and subsequent heating reduce load carrying capacity compared with isothermal conditions. Texture has a positive effect in a parallel surface contact when thermal effects are considered. It has been found that for the different convergence ratios considered, the texture enables the sustaining of a load only until a certain critical shear rate is reached. This critical shear stress depends on a number of factors such as the convergence ratio and lubricant parameters including the viscosity-temperature coefficient and the reference dynamic viscosity.

  • 5.
    Cupillard, Samuel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Thermohydrodynamics of sliding contacts with textured surfaces2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Hydrodynamic sliding contacts like those found in journal or thrust bearings are frequently encountered in various types of machinery from computers to large turbines. These contacts, involving a variation in film thickness, are used to generate pressure in the lubricant film and separate the surfaces in relative motion. The contacts must carry a load while maintaining friction as low as possible. Environmental and economic concerns require the machines to operate with minimal power consumption. A number of design modifications have been proposed over the years in order to improve performance of such hydrodynamic contacts. There are experimental indications that textured surfaces, composed of a pattern of well-defined identical shapes, can improve hydrodynamic performance. There is therefore a need to understand and explain the effects of textured surfaces on hydrodynamic contact performance. A Computational Fluid Dynamics (CFD) analysis of the flow field can provide such an understanding. The full Navier-Stokes equations are solved using CFD code for both a slider and a journal bearing. Thermal and cavitation effects are considered. Numerical techniques that deform the computational grid in time are used to recalculate the film gap and simulate the motion of a microgroove located on a moving surface.For a texture located in the inlet part of the stationary surface of an inclined slider, the pressure build-up mechanism is investigated. Such a texture decreases losses locally and allows for increased pressure and a higher load carrying capacity. A critical value of the texture depth separates positive and negative effects of inertia on the load carrying capacity of the slider. The texture studied here provides maximum efficiency when its depth is such that the lubricant flow occurs at the onset of recirculation. In 3D, the texture length should be close to the pad length to generate the highest load carrying capacity. Improvements in performance are shown for different operating conditions. One important effect is that the load carrying capacity of the slider can be increased by up to 16% under severe thermal operating conditions. A journal bearing textured with microgrooves on the stationary surface is investigated. The coefficient of friction can be reduced if grooves of suitable depth are introduced. Under light loading (eccentricity ratios less than 0.15), shallow microgrooves (with a depth less than the minimum film thickness) placed in the maximum film region increase the minimum film thickness while reducing the friction force. The load carrying capacity is enhanced based on the same principle as for the inlet textured slider. Under high loading (eccentricity ratios greater than 0.5), deep microgrooves (with a depth greater than the minimum film thickness) placed in the maximum pressure region reduce both friction force and minimum film thickness. Nevertheless, for high loading, the texture provides better reduction in friction force than a smooth bearing operating with a thinner lubricant.A microgroove positioned on the moving surface, i.e., on the shaft of a journal bearing is also studied. A 2D isothermal case is investigated to explain the effect of the microgroove on the pressure profile and the behaviour of the load carrying capacity over one shaft revolution. The microgroove decreases pressure locally at every circumferential position, resulting in a decrease in the averaged load carrying capacity. A 3D thermal case is analysed to show how lubricant transport is modified by a microgroove. The microgroove affects thermal mixing as it carries a greater amount of cold lubricant to regions with high temperatures. This effect, more pronounced with deeper microgrooves, is due to a global flow recirculation inside the microgroove, which improves mixing.

  • 6. Cupillard, Samuel
    et al.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    A CFD study of a finite textured journal bearing2008Inngår i: Hydro technology and the evironment for the new century: 24th IAHR Symposium on Hydraulic Machinery and Systems, October 27 - 31, 2008, Foz do Iguassu, Brazil, Foz do Iguassu, 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An analysis of a lubricated journal bearing is performed with special attention to the influence of textured surfaces which may improve hydrodynamic performance. The bearing is subjected to an external applied load and the force balance is fulfilled with the force of the flow acting on the bearing. The position of the shaft is fixed whereas the bearing, centred at the starting time, moves under the forces until equilibrium is reached. A mesh deformation technique is used with CFD (Computational Fluid Dynamics) in order to perform the simulations. The flow is laminar, isothermal, three-dimensional (3D) and unsteady. Cavitation is taken into account. Results are analysed with smooth and textured surfaces on the bearing. Friction force and eccentricity ratio are compared for different configurations.It is found that shallow grooves under light loading (ε < 0.15) enhance the minimum film thickness while reducing the friction force. Under high loading (ε > 0.5), deep grooves are able to reduce the friction force despite a reduced minimum film thickness. For the second case, the predicted performance is superior to those of a smooth journal bearing with thinner lubricant.

  • 7. Cupillard, Samuel
    et al.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Pressure buildup mechanism in a textured inlet of a hydrodynamic contact2008Inngår i: Journal of tribology, ISSN 0742-4787, E-ISSN 1528-8897, Vol. 130, nr 2Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A flow analysis is carried out for an inclined slider bearing with the aim of showing the governing mechanism at conditions where an optimum in load carrying capacity is achieved. The effects of surface texture on pressure buildup and load carrying capacity are explained for a textured slider bearing geometry. Numerical simulations are performed for laminar, steady, and isothermal flows. The energy transferred to the fluid from the moving wall is converted into pressure in the initial part of the converging contact and into losses in the second part. The convergence ratio can be increased, in order to get the greatest pressure gradient, until the limiting value where flow recirculation begins to occur. The texture appears to achieve its maximum efficiency when its depth is such that the velocity profile is stretched at its maximum extent without incurring incoming recirculating flow. The wall profile shape controlling the velocity profile can be optimized for many hydrodynamic contacts

  • 8. Cupillard, Samuel
    et al.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Pressure build-up mechanism in a textured inlet of a slider bearing2007Inngår i: Svenska Mekanikdagar 2007: Program och abstracts / [ed] Niklas Davidsson; Elianne Wassvik, Luleå: Luleå tekniska universitet, 2007, s. 33-Konferansepaper (Annet vitenskapelig)
  • 9.
    Cupillard, Samuel
    et al.
    Hydro-Québec Research’s Institute.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Glavatskih, Sergei
    Kungliga tekniska högskolan, KTH.
    Thermohydrodynamic analysis of a journal bearing with a microgroove on the shaft2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this study, thermohydrodynamic performance of a journal bearing with a microgroove created on the shaft is analysed. A plain journal bearing is modelled using a computational fluid dynamics (CFD) software package. Navier-Stokes and energy equations are solved. The rotor-stator interaction is treated by using a computational grid deformation technique. Results are presented in terms of typical bearing parameters as well as flow patterns. Results are also compared to the bearing with a smooth shaft. The effect induced by a microgroove on pressure distribution is explained for different bearing configurations, eccentricities and microgroove depths. It is shown that the microgroove produces a local drop in pressure which, averaged over one revolution, decreases the load carrying capacity. The load carrying capacity is further decreased by using deeper microgrooves. With thermal effects considered, the microgroove carries more cold lubricant into the warmest regions of the bearing. This effect, more pronounced with deeper microgrooves, is due to a global flow recirculation inside the microgroove, which improve mixing

  • 10. Cupillard, Samuel
    et al.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Glavatskih, Sergei
    Thermohydrodynamic analysis of a journal bearing with a microgroove on the shaft2014Inngår i: Computational Thermal Sciences, ISSN 1940-2503, E-ISSN 1940-2554, Vol. 6, nr 1, s. 47-57Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, thermohydrodynamic performance of a journal bearing with a microgroove created on the shaft is analyzed. A plain journal bearing is modeled using a computational fluid dynamics (CFD) software package. Navier-Stokes and energy equations are solved. The rotor-stator interaction is treated by using a computational grid deformation technique. The goal is to examine the pressure/temperature distribution in the bearing film. Results are presented in terms of typical bearing parameters as well as flow patterns. Results are also compared to the bearing with a smooth shaft. The effect induced by a microgroove on pressure distribution is explained for different bearing configurations, eccentricities, and microgroove depths. It is shown that the microgroove produces a local drop in pressure which, averaged over one revolution, decreases the load carrying capacity. The load carrying capacity is further decreased by using deeper microgrooves. With thermal effects considered, the microgroove carries more cold lubricant into the warmest regions of the bearing. This effect, more pronounced with deeper microgrooves, is due to a global flow recirculation inside the microgroove, which improves mixing

  • 11. Cupillard, Samuel
    et al.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    3D thermodynamic analysis of a textured slider2008Inngår i: Proceedings of NORDTRIB 2008, 13th Nordic Symposium on Tribology: Scandic Rosendahl Hotel, Tampere, Finland, June 10 - 13, 2008 / [ed] Jaakko Kleemola; Arto Lehtovaara, Tampere: Tampere University of Technology, 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Analysis of a 3D inlet textured slider bearing with a temperature dependent fluid is performed. Numerical simulations are carried out for a laminar and steady flow. Hot and cold lubricant mixing in the groove is modelled and examined for different operating conditions. Thermohydrodynamic performance of the bearing is analysed for different texture lengths. Results show that texture has a stronger and positive influence on load carrying capacity when thermal effects are considered. This beneficial effect is at a maximum for the longest dimples with a length shorter than the pad length. Texture is also beneficial for the load carrying capacity when the sliding speed and inlet flow rate are varied: with an appropriate supply mass flow, load carrying capacity can be increased by 6-7% at low sliding speeds.

  • 12. Cupillard, Samuel
    et al.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    3D thermohydrodynamic analysis of a textured slider2009Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 42, nr 10, s. 1487-1495Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Analysis of a 3D inlet textured slider bearing with a temperature dependent fluid is performed. Numerical simulations are carried out for a laminar and steady flow. Hot and cold lubricant mixing in the groove is modelled and examined for different operating conditions. Thermohydrodynamic performance of the bearing is analysed for different texture lengths. Results show that texture has a stronger and positive influence on load carrying capacity when thermal effects are considered. This beneficial effect is at a maximum for the longest dimples with a length shorter than the pad length. Texture is also beneficial for the load carrying capacity when the sliding speed and inlet flow rate are varied. The load carrying capacity of the slider can be increased by up to 16% in severe operating conditions (high sliding speed).

  • 13. Cupillard, Samuel
    et al.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Computational fluid dynamics analysis of a journal bearing with surface texturing2008Inngår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 222, nr 2, s. 97-107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An analysis of a lubricated conformal contact is carried out to study the effect of surface texture on bearing friction and load carrying capacity using computational fluid dynamics. The work focuses on a journal bearing with several dimples. Two- and three-dimensional bearing geometries are considered. The full Navier-Stokes equations are solved under steady-state conditions with a multi-phase flow cavitation model.The coefficient of friction can be reduced if a texture of suitable geometry is introduced. This can be achieved either in the region of maximum hydrodynamic pressure for a bearing with high eccentricity ratio or just downstream of the maximum film for a bearing with low eccentricity ratio. An additional pressure build-up produced as a result of the surface texture has been shown at low eccentricity ratios.

  • 14. Cupillard, Samuel
    et al.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Effect of surface texturing on journal bearing performance2006Inngår i: ASIATRIB 2006: proceedings of the third Asia International Conference on Tribology, October 16-19, Kanazawa, Japan, Minato-ku: Kikai Shinkou Kaikan , 2006Konferansepaper (Fagfellevurdert)
  • 15. Cupillard, Samuel
    et al.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Inertia effects in textured hydrodynamic contacts2010Inngår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 224, nr 8, s. 751-756Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A flow analysis is carried out for a parallel textured slider to investigate the role of fluid inertia. Numerical simulations are performed for a laminar, two-dimensional, steady and isothermal flow. Stokes solutions are compared with Navier-Stokes solutions at the same Reynolds number. A range of texture depths is analysed. It is shown that there is an optimum value of texture depth that provides maximum load-carrying capacity. It is also shown that there is a critical depth value. Inertia has a negative effect on the load-carrying capacity for depths higher than the critical value, whereas it has a positive effect for lower depths. For a given texture depth, these effects are amplified as the Reynolds number increases. The global effect of inertia is positive when a realistic configuration of a parallel textured slider with a fore-region is considered.

  • 16. Cupillard, Samuel
    et al.
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Thermal analysis of lubricant flow in a textured inlet contact2008Inngår i: Proceedings of the 19th International Symposium on Transport Phenomena (ISTP-19): Reykjavik, Iceland, August 17-21, 2008 / [ed] Sigurdur Brynjolfsson; Olafur Petur Palsson; Jong H. Kim, University of Iceland, Faculty of Industrial Engineering, Mechanical Engineering and Computer Science , 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Performance of an inlet textured contact is analysed for a temperature dependent lubricant flow. Thermal effects are analysed for different shear rates. Shearing of lubricant and subsequent heating reduce load carrying capacity and frictional losses compared with isothermal conditions. Load carrying capacity of a parallel surface contact can be improved by using texturing at the inlet when thermal effects are considered. It is also shown that for the different convergence ratios considered, the texture enables the sustaining of a load until a certain critical shear rate is reached. This critical shear rate depends on a number of factors such as the convergence ratio and lubricant parameters including the viscosity-temperature coefficient and the dynamic viscosity at reference temperature.

  • 17. Jourak, Amir
    et al.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Cupillard, Samuel
    Glavatskih, Sergei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    CFD analysis of a journal bearing with a microgroove on the shaft2008Inngår i: Proceedings of the 19th International Symposium on Transport Phenomena (ISTP-19): Reykjavik, Iceland, August 17-21, 2008 / [ed] Sigurdur Brynjolfsson; Olafur Petur Palsson; Jong H. Kim, University of Iceland, Faculty of Industrial Engineering, Mechanical Engineering and Computer Science , 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Journal bearings are used in many applications. An increase of their load carrying capacity and/or decrease of their losses may allow for savings of an enormous amount of energy. One way to enhance the characteristics of journal bearings is to modify the surface texture of the stator. The purpose of the present study is to investigate the influence of a textured rotor on journal bearing characteristics. Computational Fluid Dynamics is used to model the flow between the rotor and the journal. The full Navier-Stokes equations are solved under unsteady conditions with the commercial software ANSYS CFX 11. A two-dimensional geometry is used to model the bearing. In order to make a simulation, a separate rotor and stator are made and are attached to each other using a rotor-stator interface. Firstly, a single mesh for the smooth journal bearing is used to evaluate possible numerical artefacts created by the interface. The results illustrate a difference of 2.8 % in the load carrying capacity. Simulation with a dimpled rotor followed. Comparison between a dimpled rotor and smooth rotor shows no significant increase in load carrying capacity of the journal bearing when thermal effects are not taken into account.

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