scholarly journals A Study of Hydromagnetic Longitudinal Rough Circular Step Bearing

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Jatinkumar V. Adeshara ◽  
M. B. Prajapati ◽  
G. M. Deheri ◽  
R. M. Patel
Keyword(s):  
Standard Deviation ◽  
Type Equation ◽  
Squeeze Film ◽  
Graphical Form ◽  
Load Bearing Capacity ◽  
Random Roughness ◽  
Supply Pressure ◽  
Longitudinal Roughness ◽  
Negative Effect ◽  
Bearing System

This article discusses the effect of longitudinal roughness on the performance of hydromagnetic squeeze film in circular step bearing. To characterize the random roughness of the bearing surfaces the stochastic model of Christensen and Tonder has been employed. The stochastically averaged Reynolds’ type equation is solved using suitable boundary conditions to obtain the pressure distribution and then the load bearing capacity is computed. The results are presented in graphical form. The graphical results presented here establish that the hydromagnetic lubrication offers significant help to the longitudinal roughness pattern to enhance the performance of the bearing system. Of course, conductivities of the plates, standard deviation, and the supply pressure contribute towards reducing the negative effect induced by variance (+ve) and skewness (+ve).

scholarly journals A Comparative Study on the Ferrofluid Flow Models with Regards to the Behavior of A Ferrofluid Based Curved Rough Porous Circular Squeeze Film with Slip Velocity

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Jimit R Patel1 ◽  
G M Deheri2
Keyword(s):  
Surface Roughness ◽  
Fluid Flow ◽  
Stochastic Model ◽  
Slip Velocity ◽  
Type Equation ◽  
Squeeze Film ◽  
Load Bearing Capacity ◽  
Flow Models ◽  
The Impact ◽  
Bearing System

This investigation plans to introduce a correlation among all the three magnetic fluid flow models (Neuringer-Rosensweig’s model, Shliomis’s model, Jenkins’s model) with regards to the conduct of a ferrofluid based curved rough porous circular squeeze film with slip velocity. The Beavers and Joseph's slip velocity has been invoked to assess the impact of slip velocity. Further, the stochastic model of Christensen and Tonder has been utilized to contemplate the impact of surface roughness. The load bearing capacity of the bearing system is found from the pressure distribution which is derived from the related stochastically averaged Reynolds type equation. The graphical portrayals guarantee that Shliomis model might be favoured for preparation of the bearing system with improved life period. However, for lower to moderate values of slip Neuringer-Rosensweig model might be considered. Morever, when the slip is at least the Jenkin's model might be deployed when the roughness is at reduced level.

scholarly journals Numerical Modelling of Squeeze Film Performance between Rotating Transversely Rough Curved Circular Plates under the Presence of a Magnetic Fluid Lubricant

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Nikhilkumar D. Abhangi ◽  
G. M. Deheri
Keyword(s):  
Magnetic Fluid ◽  
Random Variable ◽  
Squeeze Film ◽  
Circular Plates ◽  
Random Roughness ◽  
Load Carrying ◽  
Nonzero Mean ◽  
Mean Variance ◽  
Positive Effect ◽  
Bearing System

An endeavour has been made to study and analyze the behaviour of a magnetic fluid-based squeeze film between curved transversely rough rotating circular plates when the curved upper plate lying along a surface determined by an exponential function approaches the curved lower plate along the surface governed by a secant function. A magnetic fluid is used as the lubricant in the presence of an external magnetic field oblique to the radial axis. The random roughness of the bearing surfaces is characterised by a stochastic random variable with nonzero mean, variance, and skewness. The associated nondimensional averaged Reynolds equation is solved with suitable boundary conditions in dimensionless form to obtain the pressure distribution, leading to the expression for the load carrying capacity. The results establish that the bearing system registers an enhanced performance as compared to that of the bearing system dealing with a conventional lubricant. This investigation proves that albeit the bearing suffers due to transverse surface roughness, there exist sufficient scopes for obtaining a relatively better performance in the case of negatively skewed roughness by properly choosing curvature parameters and the rotation ratio. It is appealing to note that the negative variance further enhances this positive effect.

scholarly journals Effect of Surface Roughness on the Squeeze Film Lubrication of Finite Poroelastic Partial Journal Bearings with Couple Stress Fluids: A Special Reference to Hip Joint Lubrication

2014 ◽  
Vol 2014 ◽  
pp. 1-13
Author(s):  
N. B. Naduvinamani ◽  
G. K. Savitramma
Keyword(s):  
Surface Roughness ◽  
Couple Stress ◽  
Stochastic Theory ◽  
Couple Stress Fluid ◽  
Squeeze Film ◽  
Hip Joints ◽  
Random Roughness ◽  
Couple Stresses ◽  
Longitudinal Roughness ◽  
Transverse Roughness

A simplified mathematical model has been developed for understanding the combined effects of surface roughness and couple stresses on the squeeze film behavior of poroelastic bearings in general and that of hip joints in particular. The cartilage is modeled as biphasic poroelastic matrix and synovial fluid is modeled as couple stress fluid. The modified form of averaged Reynolds equation which incorporates the randomized roughness structure as well as elastic nature of articular cartilage with couple stress fluid as lubricant is derived. For the study of rough surfaces, Christensen's stochastic theory is used to study the effect of two types of one-dimensional random roughness, namely, longitudinal roughness pattern and the transverse roughness pattern. The averaged film pressure distribution equations are solved numerically by using the conjugate gradient method. It is observed that the surface roughness effect is dominant and pattern dependent and the influence of couple stresses is to improve the joint performance.

Effects of Surface Roughness and Non-Newtonian Micropolar Fluid Squeeze Film between Conical Bearings

2017 ◽  
Vol 72 (12) ◽  
pp. 1151-1158 ◽  
Author(s):  
P. S. Rao ◽  
Birendra Murmu ◽  
Santosh Agarwal
Keyword(s):  
Surface Roughness ◽  
Response Time ◽  
Micropolar Fluid ◽  
Load Capacity ◽  
Squeeze Film ◽  
Graphical Form ◽  
Load Carrying ◽  
Transverse Roughness ◽  
Improved Performance ◽  
Bearing System

AbstractBased on the micropolar fluid models of Eringen and Christensen’s stochastic theories, the analysis of the effects of surface roughness and the squeeze film lubrication problems between conical bearings are presented. The concerned nondimensional Reynolds equation is solved with appropriate boundary conditions in dimensionless form to find the pressure distribution, which is then used to obtain the expression for load-carrying capacity, paving the way for the calculation of response time. Computed values of pressure, load capacity, and response time are displayed in graphical form. This investigation reveals that the bearing system admits an improved performance as compared with that of a bearing system working with a conventional lubricant. According to the results, the effects of transverse roughness provide an increase in the bearing characteristics as compared with the smooth bearing lubricated with micropolar fluid whereas the influences of longitudinal roughness yield a reversed trend. The quantifiable effects of rough surfaces and non-Newtonian fluids on bearing performances are more pronounced for the roughness and micropolar parameters.

Behaviour of Magnetic Fluid Based Rough Rayleigh Step Bearing

2012 ◽  
Author(s):  
P. A. Patel ◽  
G. M. Deheri ◽  
A. R. Patel
Keyword(s):  
Magnetic Fluid ◽  
Hydrodynamic Lubrication ◽  
Random Variable ◽  
Point Of View ◽  
Graphical Form ◽  
Slider Bearing ◽  
Negative Effect ◽  
Transverse Roughness ◽  
Established Fact ◽  
Bearing System

The Rayleigh step bearing is considered in one dimensional geometry. It is a well established fact that the roughness has a significant effect on the performance of the hydrodynamic lubrication of a slider bearing. An attempt has been made to study and analyze the effect of transverse roughness in the presence of a magnetic fluid for a Rayleigh step bearing. The bearing surfaces are assumed to be transversely rough. The roughness of the surfaces has been characterized by a random variable with non-zero mean, variance and skewness. The stochastically averaged Reynolds equation is solved with suitable boundary conditions to obtain the pressure distribution in turn, which is used to get the load carrying capacity. The results presented in graphical form indicate that the effect of transverse roughness is significantly adverse. However, this article establishes that there exist sufficient scopes for improving the performance of the bearing system in the case of negatively skewed roughness especially, when negative variance is involved, in spite of the fact that the standard deviation introduces a negative effect. Besides, the performance of the bearing system improves significantly owing to the presence of the magnetic fluid lubricant. The adverse effect of roughness can be minimized by the positive effect of magnetization at least in the case of negatively skewed roughness. Therefore, this investigation offers some measures even from bearing’s life period point of view.

scholarly journals Ferrofluid lubrication of a parallel plate squeeze film bearing

2003 ◽  
pp. 221-240 ◽  
Author(s):  
Rajesh Shah ◽  
M.V. Bhat
Keyword(s):  
Response Time ◽  
Parallel Plate ◽  
Load Capacity ◽  
Type Equation ◽  
Material Constant ◽  
Porous Matrix ◽  
Squeeze Film ◽  
Graphical Form ◽  
Anisotropic Permeability ◽  
Effects Of Rotation

We derived a Reynolds type equation for a ferrofluid lubrication in a squeeze film between two circular plates using Jenkins model and considering combined effects of rotation of the plates, anisotropic permeability in the porous matrix and slip velocity at the interface of porous matrix and film region. We used it to study the case of a parallel-plate squeeze film bearing. Expressions were obtained for dimensionless pressure, load capacity and response time. Computed values were displayed some in tabular form and some in graphical form. The load capacity decreased with increasing values of the radial permeability and attained a minimum when the plates rotated in the opposite directions with nearly the same speed. It increased with increasing values of the axial permeability or material constant of Jenkins model and attained a maximum when the value of the material constant was near unity. It increased or decreased for increasing values of the speed of rotation of the upper plate according as the value of the material constant is zero or not. The response time slowly decreased with increasing values of the radial permeability, speed of rotation of upper plate or the material constant. But, it increased with increasing values of the axial permeability and attained a maximum when the plates rotated in opposite directions with nearly the same speed. Anisotropic permeability affected the bearing characteristics considerably.

Numerical investigation of dynamic and hydrodynamic characteristics of the pad in the fluid pivot journal bearing

2021 ◽  
pp. 135065012110330
Author(s):  
Tuyen Vu Nguyen ◽  
Weiguang Li
Keyword(s):  
Computational Models ◽  
Journal Bearing ◽  
Squeeze Film ◽  
Hydrodynamic Characteristics ◽  
Hydrodynamic Properties ◽  
Squeeze Film Damper ◽  
Lubricant Oil ◽  
Oil Flow ◽  
Flow Through ◽  
Bearing System

The dynamic and hydrodynamic properties of the pad in the fluid pivot journal bearing are investigated in this paper. Preload coefficients, recess area, and size gap, which were selected as input parameters to investigate, are important parameters of fluid pivot journal bearing. The pad’s pendulum angle, lubricant oil flow through the gap, and recess pressure which characterizes the squeeze film damper were investigated with different preload coefficients, recess area, and gap sizes. The computational models were established and numerical methods were used to determine the equilibrium position of the shaft-bearing system. Since then, the pendulum angle of the pad, liquid flow, and recess pressure were determined by different eccentricities.

The load-bearing capacity of a continuous-flow squeeze film of liquid

1978 ◽  
Vol 34 (1) ◽  
pp. 25-47 ◽  
Author(s):  
D. R. Oliver ◽  
R. C. Ashton ◽  
G. D. Wadelin
Keyword(s):  
Bearing Capacity ◽  
Continuous Flow ◽  
Squeeze Film ◽  
Load Bearing Capacity ◽  
Load Bearing

The Influence of Lubricant Supply Conditions and Bearing Configuration on the Performance of (Semi) Floating Ring Bearing Systems for Turbochargers

2017 ◽  
Author(s):  
Luis San Andrés ◽  
Feng Yu ◽  
Kostandin Gjika
Keyword(s):  
Heat Flow ◽  
Thermal Energy ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Engine Oil ◽  
Large Temperature ◽  
Oil Viscosity ◽  
Supply Pressure ◽  
The Impact ◽  
Bearing System

Engine oil lubricated (semi) floating ring bearing (S)FRB systems in passenger vehicle turbochargers (TC) operate at temperatures well above ambient and must withstand large temperature gradients that can lead to severe thermo-mechanical induced stresses. Physical modeling of the thermal energy flow paths and an effective thermal management strategy are paramount to determine safe operating conditions ensuring the TC component mechanical integrity and the robustness of its bearing system. On occasion, the selection of one particular bearing parameter to improve a certain performance characteristic could be detrimental to other performance characteristics of a TC system. The paper details a thermohydrodynamic model to predict the hydrodynamic pressure and temperature fields and the distribution of thermal energy flows in the bearing system. The impact of the lubricant supply conditions (pressure and temperature), bearing film clearances, oil supply grooves on the ring ID surface are quantified. Lubricating a (S)FRB with either a low oil temperature or a high supply pressure increases (shear induced) heat flow. A lube high supply pressure or a large clearance allow for more flow through the inner film working towards drawing more heat flow from the hot journal, yet raises the shear drag power as the oil viscosity remains high. Nonetheless, the peak temperature of the inner film is not influenced much by the changes on the way the oil is supplied into the film as the thermal energy displaced from the hot shaft into the film is overwhelming. Adding axial grooves on the inner side of the (S)FRB improves its dynamic stability, albeit increasing the drawn oil flow as well as the drag power and heat flow from the shaft. The predictive model allows to identify a compromise between different parameters of groove designs thus enabling a bearing system with a low power consumption.

scholarly journals Analytical and Experimental Investigation of the Stability of the Rotor-Bearing System of a New Small Turbocharger

1987 ◽  
Author(s):  
H. R. Born
Keyword(s):  
Experimental Investigation ◽  
Dynamic Stability ◽  
Squeeze Film ◽  
Test Results ◽  
Flow Capacity ◽  
Squeeze Film Dampers ◽  
Rotor Bearing ◽  
The Stability ◽  
Turbine Design ◽  
Bearing System

This paper presents an overview of the development of a reliable bearing system for a new line of small turbochargers where the bearing system has to be compatible with a new compressor and turbine design. The first part demonstrates how the increased weight of the turbine, due to a 40 % increase in flow capacity, influences the dynamic stability of the rotor-bearing system. The second part shows how stability can be improved by optimizing important floating ring parameters and by applying different bearing designs, such as profiled bore bearings supported on squeeze film dampers. Test results and stability analyses are included as well as the criteria which led to the decision to choose a squeeze film backed symmetrical 3-lobe bearing for this new turbocharger design.

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