scholarly journals Toward Investigation of External Oil Flow From a Journal Bearing in an Epicyclic Gearbox

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Martin Berthold ◽  
Hervé Morvan ◽  
Colin Young ◽  
Richard Jefferson-Loveday
Keyword(s):  
Journal Bearing ◽  
Phase Interface ◽  
Three Dimensional ◽  
High Viscosity ◽  
Design Tool ◽  
Jet Engines ◽  
Sector Model ◽  
Bearing Life ◽  
Oil Flow ◽  
High Viscosity Oil

High loads and bearing life requirements make journal bearings the preferred choice for use in high-power, planetary gearboxes in jet engines. With the planet gears rotating about their own axis and orbiting around the sun gear, centrifugal forces generated by both motions interact with each other and create complex kinematic conditions. This paper presents a literature and state-of-the-art knowledge review to identify existing work performed on cases similar to external journal bearing oil flow. In order to numerically investigate external journal bearing oil flow, an approach to decompose an actual journal bearing into simplified models is proposed. Preliminary modeling considerations are discussed. The findings and conclusions are used to create a three-dimensional (3D), two-component computational fluid dynamics (CFD) sector model with rotationally periodic boundaries of the most simplistic approximation of an actual journal bearing: a nonorbiting representation, rotating about its own axis, with a circumferentially constant, i.e., concentric, lubricating gap. In order to track the phase interface between the oil and the air, the volume of fluid (VoF) method is used. External journal bearing oil flow is simulated with a number of different mesh densities. Two different operating temperatures, representing low and high viscosity oil, are used to assess the effect on the external flow field behavior. In order to achieve the future objective of creating a design tool for routine use, key areas are identified in which further progress is required.

scholarly journals Multiphase CFD Modeling of External Oil Flow From a Journal Bearing

2018 ◽  
Author(s):  
Martin Berthold ◽  
Hervé Morvan ◽  
Richard Jefferson-Loveday ◽  
Benjamin C. Rothwell ◽  
Colin Young
Keyword(s):  
Boundary Conditions ◽  
Journal Bearing ◽  
Flow Behavior ◽  
Phase Interface ◽  
Numerical Schemes ◽  
Ansys Fluent ◽  
Oil Film ◽  
Reconstruction Scheme ◽  
Geometric Reconstruction ◽  
Oil Flow

High loads and bearing life requirements make journal bearings a potential choice for use in high power, epicyclic gearboxes in jet engines. Particularly in a planetary configuration the kinematic conditions are complex. With the planet gears rotating about their own axis and orbiting around the sun gear, centrifugal forces generated by both motions interact with each other and affect the external flow behavior of the oil exiting the journal bearing. Computational Fluid Dynamics (CFD) simulations using the Volume of Fluid (VoF) method are carried out in ANSYS Fluent [1] to numerically model the two-phase flow behavior of the oil exiting the bearing and merging into the air surrounding the bearing. This paper presents an investigation of two numerical schemes that are available in ANSYS Fluent to track or capture the air-oil phase interface: the geometric reconstruction scheme and the compressive scheme. Both numerical schemes are used to model the oil outflow behavior in the most simplistic approximation of a journal bearing: a representation, rotating about its own axis, with a circumferentially constant, i.e. concentric, lubricating gap. Based on these simplifications, a three dimensional (3D) CFD sector model with rotationally periodic boundaries is considered. A comparison of the geometric reconstruction scheme and the compressive scheme is presented with regards to the accuracy of the phase interface reconstruction and the time required to reach steady state flow field conditions. The CFD predictions are validated against existing literature data with respect to the flow regime, the direction of the predicted oil flow path and the oil film thickness. Based on the findings and considerations of industrial requirements, a recommendation is made for the most suitable scheme to be used. With a robust and partially validated CFD model in place, the model fidelity can be enhanced to include journal bearing eccentricity. Due to the convergent-divergent gap and the resultant pressure field within the lubricating oil film, the outflow behavior can be expected to be very different compared to that of a concentric journal bearing. Naturally, the inlet boundary conditions for the oil emerging from the journal bearing into the external environment must be consistent with the outlet conditions from the bearing. The second part of this paper therefore focuses on providing a method to generate appropriate inlet boundary conditions for external oil flow from an eccentric journal bearing.

scholarly journals Towards Investigation of External Oil Flow From a Journal Bearing in an Epicyclic Gearbox

2017 ◽  
Author(s):  
Martin Berthold ◽  
Hervé Morvan ◽  
Colin Young ◽  
Richard Jefferson-Loveday
Keyword(s):  
Flow Field ◽  
Journal Bearing ◽  
Numerical Models ◽  
Flow Behavior ◽  
Phase Interface ◽  
Journal Bearings ◽  
Field Behavior ◽  
Oil Flow ◽  
Inlet Conditions ◽  
Near Wall

High loads and bearing life requirements make journal bearings the preferred choice for use in high power, epicyclic gearboxes in jet engines. In contrast to conventional, non-orbiting journal bearings in epicyclic star gearboxes, the kinematic conditions in epicyclic planetary arrangements are much more complex. With the planet gears rotating about their own axis and orbiting around the sun gear, centrifugal forces generated by both motions interact with each other and affect the external flow behavior of the oil exiting the journal bearing. This paper presents a literature and state-of-the-art knowledge review to identify existing work performed on cases similar to external journal bearing oil flow. In order to numerically investigate external journal bearing oil flow, an approach to decompose an actual journal bearing into simplified models is proposed. Later, these can be extended in a step-wise manner to allow key underlying physical phenomena to be identified. Preliminary modeling considerations will also be presented. This includes assessing different geometrical inlet conditions with the aim of minimizing computational requirements and different numerical models for near-wall treatment. The correct choice of near-wall treatment models is particularly crucial as it determines the bearing’s internal and external thermal behavior and properties. The findings and conclusions are used to create a three dimensional (3D), two-component computational fluid dynamic (CFD) sector model with rotationally periodic boundaries of the most simplistic approximation of an actual journal bearing: a non-orbiting representation, rotating about its own axis, with a circumferentially constant, i.e. concentric, lubricating gap. The inlet boundary conditions for simulating the external oil flow are generated by partly simulating the internal oil flow within the lubricating gap. In order to track the phase interface between the oil and the air surrounding the bearing, the Volume of Fluid (VoF) method is used. The quality of the CFD simulations of the domain of interest is not only dependent on the accuracy of the inlet conditions, but is also dependent on the computational mesh type, cell count, cell shape and numerical methods used. External journal bearing oil flow was simulated with a number of different mesh densities and the effect on the flow field behavior will be discussed. Two different operating temperatures, representing low and high viscosity oil, were used and their effect on the flow field behavior will also be assessed. In order to achieve the future objective of creating a design tool for routine use, key areas will be identified in which further progress is required. This includes the need to progressively increase the model fidelity to eventually simulate an orbiting journal bearing in planetary configuration with an eccentric, i.e. convergent-divergent, lubricating gap.

Two-Phase Filtration Model for Nonlinear Viscoplastic Oil and Hard Water Drive

2014 ◽  
Vol 698 ◽  
pp. 679-682
Author(s):  
Anastasia Markelova ◽  
Artem Trifonov ◽  
Valeria Olkhovskaya
Keyword(s):  
Hard Water ◽  
Component Composition ◽  
High Viscosity ◽  
Oil Fields ◽  
Nonlinear Dependence ◽  
Fractional Flow ◽  
Two Phase ◽  
Oil Flow ◽  
High Viscosity Oil

The article offers a method to solve Buckley-Leverett’s problem, taking into account the nonlinear dependence of the filtration rate of viscoplastic oil on the pressure gradient. This method is based on the transformation of the fractional flow function by introducing in the theory of water drive the equations reflecting the rheological features of the oil flow. The resulting model allows us to quantify the influence of rheological factors on the completeness of the water-oil displacement and to calculate the performance, taking into account the component composition of the hydrocarbon phases. Taking the Samara Region oil fields as an example, the article shows that the quality of design is unsatisfactory when the bundled software being used does not take into account specific non-Newtonian properties of the high-viscosity oil.

Direct numerical simulation of a turbulent core-annular flow with water-lubricated high viscosity oil in a vertical pipe

2018 ◽  
Vol 849 ◽  
pp. 419-447 ◽  
Author(s):  
Kiyoung Kim ◽  
Haecheon Choi
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Pipe Flow ◽  
Annular Flow ◽  
Volume Fraction ◽  
Phase Interface ◽  
High Viscosity ◽  
Vertical Pipe ◽  
The Core ◽  
High Viscosity Oil

The characteristics of a turbulent core-annular flow with water-lubricated high viscosity oil in a vertical pipe are investigated using direct numerical simulation, in conjunction with a level-set method to track the phase interface between oil and water. At a given mean wall friction ($Re_{\unicode[STIX]{x1D70F}}=u_{\unicode[STIX]{x1D70F}}R/\unicode[STIX]{x1D708}_{w}=720$, where $u_{\unicode[STIX]{x1D70F}}$ is the friction velocity, $R$ is the pipe radius and $\unicode[STIX]{x1D708}_{w}$ is the kinematic viscosity of water), the total volume flow rate of a core-annular flow is similar to that of a turbulent single-phase pipe flow of water, indicating that water lubrication is an effective tool to transport high viscosity oil in a pipe. The high viscosity oil flow in the core region is almost a plug flow due to its high viscosity, and the water flow in the annular region is turbulent except for the case of large oil volume fraction (e.g. 0.91 in the present study). With decreasing oil volume fraction, the mean velocity profile in the annulus becomes more like that of turbulent pipe flow, but the streamwise evolution of vortical structures is obstructed by the phase interface wave. In a reference frame moving with the core velocity, water is observed to be trapped inside the wave valley in the annulus, and only a small amount of water runs through the wave crest. The phase interface of the core-annular flow consists of different streamwise and azimuthal wavenumber components for different oil holdups. The azimuthal wavenumber spectra of the phase interface amplitude have largest power at the smallest wavenumber whose corresponding wavelength is the pipe circumference, while the streamwise wavenumber having the largest power decreases with decreasing oil volume fraction. The overall convection velocity of the phase interface is slightly lower than the core velocity. Finally, we suggest a predictive oil holdup model by defining the displacement thickness in the annulus and considering the boundary layer characteristics of water flow. This model predicts the variation of the oil holdup with the superficial velocity ratio very well.

Multiphase Computational Fluid Dynamics Modeling of External Oil Flow From a Journal Bearing

2018 ◽  
Vol 141 (5) ◽  
Author(s):  
Martin Berthold ◽  
Hervé Morvan ◽  
Richard Jefferson-Loveday ◽  
Colin Young ◽  
Benjamin C. Rothwell ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Boundary Conditions ◽  
Journal Bearing ◽  
Flow Behavior ◽  
Phase Interface ◽  
Ansys Fluent ◽  
Reconstruction Scheme ◽  
Geometric Reconstruction ◽  
Oil Flow

High loads and bearing life requirements make journal bearings a potential choice for use in high power, epicyclic gearboxes in jet engines. Particularly, in a planetary configuration, the kinematic conditions are complex. With the planet gears rotating about their own axes and orbiting around the sun gear, centrifugal forces generated by both motions interact with each other and affect the external flow behavior of the oil exiting the journal bearing. Computational fluid dynamics (CFD) simulations using the volume of fluid (VoF) method are carried out in ANSYS fluent (ANSYS, 2013, “ANSYS Fluent User's Guide,” ANSYS Inc., Canonsburg, PA) to numerically model the two-phase flow behavior of the oil exiting the bearing and merging into the air surrounding the bearing. This paper presents an investigation of two numerical schemes that are available in ansysfluent to track or capture the air–oil phase interface: the geometric reconstruction scheme and the compressive scheme. Both numerical schemes are used to model the oil outflow behavior in the most simplistic approximation of a journal bearing: a representation, rotating about its own axis, with a circumferentially constant, i.e., concentric, lubricating gap. Based on these simplifications, a three-dimensional (3D) CFD sector model with rotationally periodic boundaries is considered. A comparison of the geometric reconstruction scheme and the compressive scheme is presented with regard to the accuracy of the phase interface reconstruction and the time required to reach steady-state flow-field conditions. The CFD predictions are validated against existing literature data with respect to the flow regime, the direction of the predicted oil flow path, and the oil film thickness. Based on the findings and considerations of industrial requirements, a recommendation is made for the most suitable scheme to be used. With a robust and partially validated CFD model in place, the model fidelity can be enhanced to include journal bearing eccentricity. Due to the convergent-divergent gap and the resultant pressure field within the lubricating oil film, the outflow behavior can be expected to be very different compared to that of a concentric journal bearing. Naturally, the inlet boundary conditions for the oil emerging from the journal bearing into the external environment must be consistent with the outlet conditions from the bearing. The second part of this paper therefore focuses on providing a method to generate appropriate inlet boundary conditions for external oil flow from an eccentric journal bearing.

scholarly journals Prospects of High Viscosity Oil Flow Rate in Horizontal Wells

2021 ◽  
Author(s):  
Sudad H Al-Obaidi ◽  
Galkin AP ◽  
Patkin AA
Keyword(s):  
Fluid Flow ◽  
Pressure Gradient ◽  
Flow Rate ◽  
Pore Space ◽  
Analytical Formula ◽  
High Viscosity ◽  
Pressure Gradients ◽  
Oil Flow ◽  
Molecular Components ◽  
High Viscosity Oil

The non-Newtonian nature of fluid flow represents one of the most important features of the development of high-viscosity oil (HVO) deposits .The deviation from the linear law of the fluid flow is associated, first of all, with the formation of a strong spatial structure due to the presence of high-molecular components and dissolved gases in the composition. The stress required to destroy the formed structure is called the shear stress of the ultimate destruction of the structure. In this regard, in order to ensure the flow of HVO through the pore space, it is necessary to create certain values of pressure gradients above the dynamic shear pressure gradient (DSPG). With increasing pressure gradients above the DSPG, the oil structure begins to collapse, and after overcoming the critical value of the pressure gradient of the ultimate destruction of the structure (PGUDS), flow begins to be described by the Newtonianlaw. The article considers the influence of various factors on the oil flow rate of a horizontal well (HW) that exploits the HVO Deposit. At the same time, numerical experiments were carried out on a hydrodynamic model for the non-Newtonian oil flow regime (in the presence of DSPG) and the results obtained were compared with calculations of the oil flow rate using an analytical formula.

Experimental investigation on two-phase air/high-viscosity-oil flow in a horizontal pipe

2011 ◽  
Vol 66 (23) ◽  
pp. 5968-5975 ◽  
Author(s):  
C. Foletti ◽  
S. Farisè ◽  
B. Grassi ◽  
D. Strazza ◽  
M. Lancini ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
High Viscosity ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Oil Flow ◽  
High Viscosity Oil

scholarly journals Numerical Investigation of Turbulence Models for a Superlaminar Journal Bearing

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Aoshuang Ding ◽  
Xiaodong Ren ◽  
Xuesong Li ◽  
Chunwei Gu
Keyword(s):  
Experimental Data ◽  
Buffer Layer ◽  
Journal Bearing ◽  
Profile Analysis ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Fully Developed Turbulence ◽  
Developed Turbulence ◽  
Sst Model ◽  
Oil Flow

With rotating machineries working at high speeds, oil flow in bearings becomes superlaminar. Under superlaminar conditions, flow exhibits between laminar and fully developed turbulence. In this study, superlaminar oil flow in an oil-lubricated tilting-pad journal bearing is analyzed through computational fluid dynamics (CFD). A three-dimensional bearing model is established. CFD results from the laminar model and 14 turbulence models are compared with experimental findings. The laminar simulation results of pad-side pressure are inconsistent with the experimental data. Thus, the turbulence effects on superlaminar flow should be considered. The simulated temperature and pressure distributions from the classical fully developed turbulence models cannot correctly fit the experimental data. As such, turbulence models should be corrected for superlaminar flow. However, several corrections, such as transition correction, are unsuitable. Among all the flow models, the SST model with low-Re correction exhibits the best pressure distribution and turbulence viscosity ratio. Velocity profile analysis confirms that a buffer layer plays an important role in the superlaminar boundary layer. Classical fully developed turbulence models cannot accurately predict the buffer layer, but this problem can be resolved by initiating an appropriate low-Re correction. Therefore, the SST model with low-Re correction yields suitable results for superlaminar flows in bearings.

scholarly journals High Viscosity Land Based Oil Flow Model

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Daniel Mendelsohn ◽  
Eric Comerma ◽  
Matt Bernardo ◽  
Jeremy Fontenault ◽  
Sitara Baboolal
Keyword(s):  
Shear Stress ◽  
Pressure Gradient ◽  
Flow Model ◽  
High Viscosity ◽  
Surface Boundary ◽  
Viscous Oil ◽  
Oil Flow ◽  
Downslope Flow ◽  
High Viscosity Oil ◽  
Highly Viscous Oil

ABSTRACT Highly viscous oil does not behave the same as other regular liquid hydrocarbon mixtures. To evaluate the effects of a potential land-based blowout on the surrounding environment, RPS implemented a multi-step approach to simulate the trajectory and fate of high viscosity oil downslope flow. If spilled on land, initially warm oil cools and tends to gel, implying a non-Newtonian flow. To predict the behavior of high viscosity oil as it flows downslope, spreads and cools, RPS developed a new unique land-based spill model. The behavior of highly viscous crude oil has many similarities to volcanic lava flows, particularly the stark changes in oil viscosity and shear stress as the fluid cools. This study describes a “lava” flow numerical model developed to simulate the response of high viscosity oils. The viscous flow model is based on the lava model of Griffiths (2000) which simulates the unconfined motion of a Bingham fluid down a plane of constant slope. The model allows all physical and chemical parameters to vary continuously downslope. The lateral flow is assumed to cease when the cross-slope pressure gradient is balanced by the basal-yield stress also giving the height of the flow (H) on the center line of the flow as a function of shear stress. For oil flow motion the downslope pressure gradient must be greater than the oil shear stress and hence there is a critical height, based on the local oil shear stress and slope, below which there will be no downslope motion. An atmospheric heat transfer equation was applied to the oil surface as the surface boundary condition. The model was applied to a hypothetical on land release of highly viscous oil in a one-dimensional, downslope form, where the ground slope was assumed constant along the flow path. As the oil progresses downslope, its temperature was updated each time step in each cell and used to calculate new oil properties for density, specific heat, viscosity, and shear stress. The model results provide information about the rate and total distance travelled and time for the downslope flow to stop.

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