Leakage-free optimization of micro herringbone grooved journal bearings with a virtual node method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lei Yin ◽  
Xiaolin Zheng ◽  
Dongxing Tang ◽  
Yanfeng Han ◽  
Rui Zhao ◽  
...  
Keyword(s):  
Friction Force ◽  
Numerical Algorithm ◽  
Design Methodology ◽  
Load Capacity ◽  
Groove Depth ◽  
Journal Bearings ◽  
Virtual Node ◽  
Content Type ◽  
Leakage Model ◽  
Critical Nodes

Purpose This study aims to develop a new method to treat the numerical singularity at the critical nodes of two skew coordinates, and optimize the leakage of micro herringbone grooved journal bearings (MHGJBs) with this method. Design/methodology/approach A side leakage numerical algorithm is proposed by using the skew meshes with a virtual node (SMVN) method to evaluate the effects of groove angle, bank/groove ratio, groove depth and groove number on load capacity, friction and side leakage of MHGJB. Findings The SMVN method is effective in treating the numerical singularity at the critical nodes of two skew coordinates. Besides, a group of optimized parameters of micro herringbone groove is obtained which can not only minimize the side leakage but also improve the load capacity and friction force. Originality/value A virtual node method was proposed, which can significantly improve the calculation accuracy in the side leakage model.

Effect of non-Newtonian magneto-elastohydrodynamic on performance characteristics of slider-bearings

2019 ◽  
Vol 71 (10) ◽  
pp. 1158-1165
Author(s):  
Mouhcine Mouda ◽  
Mohamed Nabhani ◽  
Mohamed El Khlifi
Keyword(s):  
Friction Coefficient ◽  
Design Methodology ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Transverse Magnetic ◽  
Finite Width ◽  
Two Dimensional ◽  
Content Type ◽  
Slider Bearings ◽  
First Time

Purpose This study aims to examine the magneto-elastohydrodynamic effect on finite-width slider-bearings lubrication using a non-Newtonian lubricant. Design/methodology/approach Based on the magneto-hydrodynamic (MHD) theory and Stokes micro-continuum mechanics, the modified two-dimensional Reynolds equation including bearing deformation was derived. Findings It is found that the bearing deformation diminishes the load-capacity and increases the friction coefficient in comparison with the rigid case. However, the non-Newtonian effect increases load-capacity but decreases the friction coefficient. Moreover, the use of a transverse magnetic field increases both the friction coefficient and load capacity. Originality/value This study combines for the first time MHD and elastic deformation effects on finite-width slider-bearings using a non-Newtonian lubricant.

Effect of torque ratio on speed regulating start

2018 ◽  
Vol 70 (9) ◽  
pp. 1657-1663
Author(s):  
Qingrui Meng ◽  
Zhao Chenghao ◽  
Tian Zuzhi
Keyword(s):  
Film Thickness ◽  
Theoretical Basis ◽  
Design Methodology ◽  
Load Capacity ◽  
Load Torque ◽  
Content Type ◽  
Oil Film ◽  
Torque Transmission ◽  
Drive Speed ◽  
Starting Process

Purpose Friction pairs of the hydro-viscous drive speed regulating start device should be designed based on the rated torque. To obtain design basis of the rated torque of the hydro-viscous drive speed regulating start device, studies on effect of torque ratio (a ratio of the load torque to the rated torque) on speed regulating start were carried out theoretically and experimentally. Design/methodology/approach Under different torque ratio, the modified Reynolds, the thermal energy and the viscosity-temperature equations were solved simultaneously by using finite element method to reveal variation laws of the oil film load capacity and torque transmission during the starting process. Then, speed regulating start experiments were carried out to study the following performance of the output speed. Findings The results show that oil film thickness decreases with the increase of the torque ratio; when oil film thickness is less than 0.05 mm, oil film temperature increases rapidly with the decrease of oil film thickness, which eventually deteriorates performance of the speed regulating start; when the torque ratio decreases to about 0.3, output speed shows a better following performance. Originality/value It indicates that, to acquire a better speed regulating start, the rated torque of the hydro-viscous drive speed regulating start device should not be less than three times of the load torque. Achievements of this work provide theoretical basis for optimal design of the friction pairs of the hydro-viscous drive speed regulating start device.

Effects of structural parameters of oil groove on transmission characteristics of hydro-viscous clutch based on viscosity-temperature property of oil film

2017 ◽  
Vol 69 (5) ◽  
pp. 690-700 ◽  
Author(s):  
Fangwei Xie ◽  
Diancheng Wu ◽  
Yaowen Tong ◽  
Bing Zhang ◽  
Jie Zhu
Keyword(s):  
Contact Zone ◽  
Load Capacity ◽  
Structural Parameters ◽  
Groove Depth ◽  
Central Angle ◽  
Friction Contact ◽  
Temperature Property ◽  
Pressure Flow ◽  
Content Type ◽  
Oil Film

Purpose The purpose of this paper is to study the influence of structural parameters of oil groove (such as central angle number, depth and so on) on pressure, flow, load capacity and transmitted torque between friction pairs of hydro-viscous clutch. Design/methodology/approach According to the working process of friction pairs of hydro-viscous clutch, mathematical models of hydrodynamic load capacity and torque transmitted by the oil film were built based on viscosity-temperature property. Then analytical solutions of pressure, flow, load capacity and transmitted torque were obtained; effects of central angle of oil groove zone and friction contact zone, oil film thickness, number of oil grooves on pressure, flow, load capacity and torque were studied theoretically. Findings The research found that the central angle of oil groove zone, number of oil grooves and oil groove depth have similar effects on flow, which means that with the increase of central angle, number or depth of oil grooves, the flow also increases; pressure in friction contact zone and oil groove zone drops along radial direction, whereas its value in oil groove zone is higher. With the increase of the central angle of oil groove zone, pressure in friction contact zone and friction contact zone rises, and the load capacity increases, whereas the transmitted torque drops. Number of oil grooves has little effect on load capacity. When the oil film thickness increases, its flow increases accordingly, whereas the pressure, load capacity and transmitted torque drops. Meanwhile, the transmitted torque decreases with the increase of number of oil grooves, whereas the oil groove depth nearly has no effects on transmitted torque. Originality/value In this paper, mathematical models of hydrodynamic load capacity and torque transmitted by oil film were built based on viscosity-temperature property in the working process of hydro-viscous clutch, and their analytical solutions were obtained; effects of structural parameters of oil groove on transmission characteristics of hydro-viscous clutch based on viscosity-temperature property were revealed. The research results are of great value to the theory development of hydro-viscous drive technology, the design of high-power hydro-viscous clutch and relative control strategy.

Numerical analysis of water-lubricated thrust bearing with groove texture considering turbulence and cavitation

2018 ◽  
Vol 70 (6) ◽  
pp. 1127-1136 ◽  
Author(s):  
Huihui Feng ◽  
Liping Peng
Keyword(s):  
Friction Force ◽  
Surface Texture ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Groove Width ◽  
Content Type ◽  
Cavitation Effect ◽  
Rotary Speed ◽  
Groove Texture ◽  
Laminar Model

Purpose This paper aims to establish the mathematical models for the water-lubricated thrust bearing with groove texture considering turbulence and cavitation and numerically analyze the influence of rotary speed, texture depth, groove number and groove width on the static performance of the bearing. Design/methodology/approach The turbulent Reynolds equation and the Jakobsson–Floberg–Olsson cavitation model are adopted for the analysis. The Payvar–Salant algorithm and Finite difference schemes are used to discretize the governing equations. To illustrate the influence of turbulence, the performance of the bearing predicted by the turbulent and laminar models are compared. Findings According to the results, the load capacity and the friction force calculated by the turbulent model are greater than those obtained by laminar model, and the deviation between them gradually increases with the increased rotary speed. So, the turbulent effect should be fully considered for high-speed water-lubricated bearing with surface texture. There exists a peak value for the load capacity of the water-lubricated thrust bearing in respect to the texture depth, the number of grooves and the groove width ratio, while the friction force varies slowly with those parameters. Well-designed groove texture can improve the performance of the water-lubricated thrust bearing. Originality/value This paper proposes a mathematical model considering turbulent and cavitation effect for water-lubricated thrust bearing with surface texture. This model can be complementary to conventional laminar model which is used to analyze the performance of textured bearing at low rotary speed.

Static and Dynamic Characteristics of Rolling-Pad Journal Bearings in Super-Laminar Flow Regime

1988 ◽  
Vol 110 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Makoto Mikami ◽  
Mikio Kumagai ◽  
Shuetsu Uno ◽  
Hiromu Hashimoto
Keyword(s):  
Friction Force ◽  
Dynamic Characteristics ◽  
Load Capacity ◽  
Journal Bearings ◽  
Curvature Radius ◽  
Static And Dynamic Characteristics ◽  
Oil Film ◽  
Lubrication Equation ◽  
Viscous Heat ◽  
Before And After

Static and dynamic characteristics of load-on-type rolling-pad journal bearings with six pads have been studied theoretically and experimentally by considering the effects of both turbulence and viscous heat generation in the oil film. By concurrently solving a turbulent lubrication equation and an adiabatic energy equation, pressure and temperature distributions, load capacity, and friction force are obtained. Moreover, the linearlized spring and damping coefficients of oil film are calculated under the assumption of small displacements of the journal center. It is found that the load capacity and the friction force considerably increase due to turbulence, and the effects of heat generated under turbulent conditions are more pronounced than those under laminar conditions. Also clarified are that bearing characteristics are improved by preloading the lower-side two pads located before and after the lowest pad, and that the curvature radius of the pad insignificantly affects the characteristics. The experimental results on static characteristics agree well with the theoretical results.

Design and fast verification of pocket elliptical journal bearings

2014 ◽  
Vol 66 (3) ◽  
pp. 393-401 ◽  
Author(s):  
Fabrizio Stefani
Keyword(s):  
Design Methodology ◽  
Journal Bearings ◽  
Fast Method ◽  
Analysis Method ◽  
Element Analysis ◽  
Content Type ◽  
Finite Element Analysis Method ◽  
Bearing Design ◽  
And Performance ◽  
Industrial Level

Purpose – The purpose of this paper was to conceive a fast method to verify design and performance of elliptical pocket journal bearings. Design/methodology/approach – The computer-aided verification of pocket journal bearings is performed by means of a suitable finite element analysis method. Findings – The results of sample analyses indicate that the machining tolerances are very influential on elliptical pocket bearing performances, and they must be included among the input data. Originality/value – Although elliptical pocket bearings are widely used in turbomachineries, the influence of their design on performance has not been specifically investigated. A lot of works about tribological models are available, but few of them focus on their application to bearing design at the industrial level.

Geometrical analysis of elliptical journal bearings and its effects on friction and load capacity

2019 ◽  
Vol 234 (5) ◽  
pp. 743-750
Author(s):  
Ali Ebrahimi ◽  
Saleh Akbarzadeh ◽  
Hassan Moosavi
Keyword(s):  
Friction Force ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Major Axis ◽  
Journal Bearings ◽  
Maximum Pressure ◽  
Geometrical Parameters ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Lower Temperature

Elliptical bearings are one type of non-circular journal bearings which has two main advantages over the conventional circular bearings: lower temperature rise and lower vibrations. In this study, the energy equation and Reynolds equation are simultaneously solved under adiabatic boundary conditions. The predicted pressure and temperature are compared to the results of published literature for verification purposes. A parametric study is then conducted on the effect of geometrical parameters of the elliptical journal bearing on the load capacity, friction force, pressure, and oil temperature. Effect of geometric parameters of the bearing on the performance is studied. The results show that non-circularity parameter is the most influential parameter in the bearing, and an increase in the non-circularity results in the decrease in maximum pressure and temperature as well as the friction force. Increasing the eccentricity ratio, on the other hand, will cause an increase in the pressure, temperature, and the friction force. Changes in the angle between the major axis of the bearing and load direction decrease the load-carrying capacity and the non-dimensional pressure and results in an increase in the friction coefficient.

Tribological design of hydrodynamic sliding journal bearings – formulating new functional charts

2005 ◽  
Vol 57 (1) ◽  
pp. 4-11 ◽  
Author(s):  
C. Pandazaras ◽  
G. Petropoulos
Keyword(s):  
Design Methodology ◽  
Reynolds Equation ◽  
Journal Bearings ◽  
Content Type ◽  
Topographic Features ◽  
Operational Characteristics ◽  
Innovative Methodology ◽  
Limited Length ◽  
New Type

PurposeThis paper aims to introduce an innovative methodology for the determination of operational characteristics of journal bearings (j‐bs) through using new type charts based upon a numerical solution of the Reynolds equation.Design/methodology/approachThe present paper proposes the mapping of the behaviour of a smooth, isothermal and hydrodynamic (j‐b) as a first step towards a future representation of the behaviour of j‐b's with limited length and high lubricating clearance with or without macro or micro topographic features operating under high loads, high temperatures and low linear velocities leading to conditions of mixed or boundary lubrication.FindingsThe derived analytical relationships between dimensionless quantities lead to the development of high precision synthetic operational charts regarding sliding j‐b of any given geometry and varying operational characteristics.Originality/valueBy considering the iso‐operational curves which are of a hook form relevant to comparative data becomes directly and rapidly clarified.

Viscous shear effect in non-Newtonian lubrication of finite porous elastic bearings

2019 ◽  
Vol 71 (3) ◽  
pp. 374-380 ◽  
Author(s):  
Anas Sakim ◽  
Mohamed Nabhani ◽  
Mohamed El Khlifi
Keyword(s):  
Friction Factor ◽  
Couple Stress ◽  
Load Capacity ◽  
Slip Flow ◽  
Journal Bearings ◽  
Brinkman Equation ◽  
Couple Stress Fluid ◽  
Shear Effect ◽  
Content Type ◽  
Viscous Shear

Purpose The purpose of this study is to investigate the viscous shear effect on finite porous elastic journal bearings lubricated with non-Newtonian couple stress fluid. Design/methodology/approach Based on Stokes micro-continuum mechanics, the modified Reynolds equation including bearing deformation was derived. The porous flow was modeled by the complete Darcy–Brinkman equation. To show the viscous shear effects, bearing characteristics including load capacity and friction factor are compared to those obtained from Darcy model with Beavers–Joseph slip conditions (slip flow model [SFM]) by developing a computer program and discussed for different couple stress values, permeabilities and elastic deformation parameters. Findings It is found that the viscous shearing forces effects of the Brinkman model increase the load capacity and friction factor compared to those derived using SFM. Moreover, the couple stresses increase the load capacity while decreasing the friction factor for both models. Originality/value This study introduces for the first time the viscous effect on finite porous elastic journal bearings lubricated with couple stress fluid.

Development of bearings for a small high speed cryogenic turboexpander

2012 ◽  
Vol 64 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Subrata Ghosh ◽  
Parboti Mukherjee ◽  
Sunil Sarangi
Keyword(s):  
Rotational Speed ◽  
High Speed ◽  
Design Methodology ◽  
Input Parameter ◽  
Journal Bearings ◽  
Content Type ◽  
Thrust Bearings ◽  
Academic Literature ◽  
Practical Implications ◽  
Taking Care

PurposeThe purpose of this paper is to examine the development of aerodynamic thrust bearings and aerodynamic journal bearings applied to a small high speed cryogenic turboexpander in Indian conditions.Design/methodology/approachAs a part of indigenous programme in the process of development, some input parameter was taken from the available literature and then dimensions were optimized and computed while taking care to minimize fabrication constraints.FindingsA series of tests were conducted to confirm the findings. Detailed study of the effect of stability and vibration of bearings was taken up. The maximum rotational speed obtained was 200,000 rpm.Practical implicationsThe outcome may help the designers, researchers and manufacturers of these components.Originality/valueAlthough manufacturers design and develop the bearings of turboexpanders for their production, no academic literature has been available for this purpose until now.

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