scholarly journals Ferro Fluid Based Rough Porous Tilted Pad Bearing with Slip Effect

10.29007/cns9 ◽  
2018 ◽  
Author(s):  
Snehal Shukla ◽  
Gunamani Deheri
Keyword(s):  
Load Capacity ◽  
Fluid Pressure ◽  
Closed Form Solution ◽  
Form Solution ◽  
Squeeze Film ◽  
Physical Parameters ◽  
Slip Effect ◽  
Transverse Roughness ◽  
Bearing Design ◽  
Effect Of Surface

The focus of this paper is to propose an innovative mathematical model, which describes the influence of slip and transverse roughness on a hydromagnetic squeeze film in porous tilted pad bearing. The stochastic model of Christensen and Tonder is, applied to evaluate the effect of surface roughness. Beavers and Joseph slip model takes the care of slip effect. Applying these models which governing the fluid pressure; is solved for the calculation of load support. The closed form solution is, obtained for the pressure and load capacity as a function of various physical parameters. The effect of such parameters is, discussed through graphical representations. The computations indicate that slip has to be at minimum for any upgrading in the bearing design. Besides, the absence of flow fails to keep away the bearing from supporting good amount of load, which does not happen in the case of traditional lubricant.

Squeeze Film Problems of Long Partial Journal Bearings for Non-Newtonian Couple Stress Fluids with Pressure-Dependent Viscosity

2011 ◽  
Vol 66 (8-9) ◽  
pp. 512-518 ◽  
Author(s):  
Jaw-Ren Lin ◽  
Li-Ming Chu ◽  
Chi-Ren Hung ◽  
Rong-Fang Lu
Keyword(s):  
Couple Stress ◽  
Load Capacity ◽  
Perturbation Technique ◽  
Closed Form Solution ◽  
Journal Bearings ◽  
Form Solution ◽  
Squeeze Film ◽  
Pressure Dependent Viscosity ◽  
Dependent Viscosity ◽  
Couple Stress Fluids

Abstract According to the experimental work of C. Barus in Am. J. Sci. 45, 87 (1893) [1], the dependency of liquid viscosity on pressure is exponential. Therefore, we extend the study of squeeze film problems of long partial journal bearings for Stokes non-Newtonian couple stress fluids by considering the pressure-dependent viscosity in the present paper. Through a small perturbation technique, we derive a first-order closed-form solution for the film pressure, the load capacity, and the response time of partial-bearing squeeze films. It is also found that the non-Newtonian couple-stress partial bearings with pressure-dependent viscosity provide better squeeze-film characteristics than those of the bearing with constant-viscosity situation.

Homotopy Analysis of Circular Plates Squeeze Film Bearings Lubricated with Couple Stress Fluids: Piezo-Viscous Model

2020 ◽  
Vol 8 (2) ◽  
pp. 95-102
Author(s):  
J.P. Tripathi ◽  
◽  
U.P. Singh ◽  
B.K. Singh ◽  
◽  
...  
Keyword(s):  
Couple Stress ◽  
Load Capacity ◽  
Closed Form Solution ◽  
Continuum Theory ◽  
Form Solution ◽  
Squeeze Film ◽  
Bearing Plate ◽  
Homotopy Analysis ◽  
Pressure Parameter ◽  
Couple Stress Fluids

The piezo-viscous effect is crucial in fluid flows under high-pressure applications such as fluid film lubrication, microfluidics, and geophysics. We have investigated the combined influences of piezo-viscous dependence and non-Newtonian couple stresses on the performance of circular plate squeeze film bearings using Stokes Micro-Continuum theory of couple stress fluids together with the exponential variation of viscosity with pressure. A closed-form solution for film pressure has been obtained using the homotopy analysis method. The numerical results for pressure and load capacity with different values of the viscosity-pressure parameter have been calculated and compared with iso-viscous couple stress and Newtonian lubricants. An enhanced pressure and load capacity are observed in the analysis. The response time for the bearing (plate approach time) has also been calculated and a significant increase is observed.

Influence of Nanoparticles in Lubricants on the Load Capacity of Hydrostatic Thrust Bearings

2012 ◽  
Vol 486 ◽  
pp. 99-103
Author(s):  
Huei Chu Weng ◽  
Yuan Kang
Keyword(s):  
Volume Fraction ◽  
Load Capacity ◽  
Particle Volume Fraction ◽  
Closed Form Solution ◽  
Form Solution ◽  
Interparticle Interaction ◽  
Particle Volume ◽  
Thrust Bearings ◽  
Bearing Load ◽  
Thrust Pad

An analysis for the effect of nanoparticles in lubricants on load capacity is performed to study a rectangular thrust pad hydrostatic bearing with a central recess. The closed-form solution of the bearing load is derived analytically and presented for nanofluids with interparticle interaction. Results reveal that in the presence of nanoparticles, the enhanced viscosity could result in an increase in bearing load; moreover, this increase dramatically increases as particle volume fraction and/or interparticle interaction increases. The effect of nanoparticles on the bearing load can be magnified by decreasing the bearing gap.

Vp/Vs ratio and dehydration reactions in subduction zones

2020 ◽  
Author(s):  
Nicolas Brantut ◽  
Emmanuel David
Keyword(s):  
Experimental Data ◽  
Subduction Zones ◽  
Fluid Pressure ◽  
Closed Form Solution ◽  
Form Solution ◽  
Strong Increase ◽  
Seismological Data ◽  
Dehydration Reactions ◽  
Model Predictions ◽  
Effective Medium Approach

<p>High Vp/Vs ratio is a commonly used diagnostic for elevated fluid pressure when interpreting seismological data. The physical basis for this interpretation comes from rock physical data and models of isotropic, cracked rocks. Here, we establish precise conditions under which this interpretation is correct, by using an effective medium approach for fluid-saturated rocks. While the usual result of an increasing Vp/Vs with increasing fluid-saturated porosity holds for crack-like pores, we find that Vp/Vs ratio is not always monotonically increasing with increasing fluid content if the porosity shape deviates from thin cracks, and if the initial Vp/Vs of the rock (without porosity) is already quite high. This is specifically the case of dehydrating rocks, where initial Vp/Vs may already be high (>1.9 for lizardite, for instance), and where the porosity created by the dehydration reaction may be in the form of elongated needles. The model predictions are supported by existing experimental data obtained during dehydration experiments in gypsum and lizardite, which both show a significant decrease in Vp/Vs as dehydration proceeds. Although no experimental data is yet availbale on antigorite, we make a prediction that antigorite dehydration may not lead to any strong increase in Vp/Vs ratio under typical subduction zone conditions. We present our theoretical results in the form of simple closed-form solution (valid asymptotically for a range of limiting cases), which should help guide the interpretation of Vp/Vs ratio from seismological data.</p>

scholarly journals The Sustainable Characteristic of Bio-Bi-Phase Flow of Peristaltic Transport of MHD Jeffrey Fluid in the Human Body

2018 ◽  
Vol 10 (8) ◽  
pp. 2671 ◽  
Author(s):  
Ahmed Zeeshan ◽  
Nouman Ijaz ◽  
Tehseen Abbas ◽  
Rahmat Ellahi
Keyword(s):  
Volume Fraction ◽  
Closed Form Solution ◽  
Pressure Rise ◽  
Expansion Method ◽  
Form Solution ◽  
Peristaltic Transport ◽  
Jeffrey Fluid ◽  
Physical Parameters ◽  
Phase Flow ◽  
Special Cases

This study deals with the peristaltic transport of non-Newtonian Jeffrey fluid with uniformly distributed identical rigid particles in a rectangular duct. The effects of a magnetohydrodynamics bio-bi-phase flow are taken into account. The governing equations for mass and momentum are simplified using the fact that wavelength is much greater than the amplitude and small Reynolds number. A closed-form solution for velocity is obtained by means of the eigenfunction expansion method whereby pressure rise is numerically calculated. The results are graphically presented to observe the effects of different physical parameters and the suitability of the method. The results for hydrodynamic, Newtonian fluid, and single-phase problems can be respectively obtained by taking the Hartmann number (M = 0), relaxation time (λ1=0), and volume fraction (C = 0) as special cases of this problem.

Inertia Effects on the Dynamics of a Disk Levitated by Incompressible Laminar Fluid Flow

1983 ◽  
Vol 105 (3) ◽  
pp. 643-653
Author(s):  
D. K. Warinner ◽  
J. T. Pearson
Keyword(s):  
Film Thickness ◽  
Closed Form ◽  
Mass Flow ◽  
Transient Flow ◽  
Closed Form Solution ◽  
Form Solution ◽  
High Mass ◽  
Squeeze Film ◽  
Navier Stokes Equation ◽  
Inertia Effects

This paper develops a nonlinear ordinary differential equation (O.D.E.) of motion for a disk parallel to a flat plate and levitated by incompressible laminar flow of fluid supplied from a central orifice. The fluid’s inertia, reflected in high mass flow rates, is accounted for. The transient flow velocity and pressure field are found by iterative integration of the Navier-Stokes equation to determine the O.D.E. for the time-dependent height of the disk (or fluid film thickness). The film thickness is found by not only numerically integrating the O.D.E., but also by linearizing the equation to obtain a closed-form solution. The results of this combined squeeze-film, source-flow case compare favorably with experimental data presented which span cases from negligible inertia (viscous dominance) to cases of inertia dominance. Fortunately, the closed-form solution differs only slightly from the numerical solution; this provides relatively accurate expressions for the frequencies and damping coefficients in terms of the geometry, load (or weight of disk), mass flow rate, and the fluid properties.

Squeeze Films for Rectangular Plates

1963 ◽  
Vol 85 (2) ◽  
pp. 243-246 ◽  
Author(s):  
Donald F. Hays
Keyword(s):  
Thin Film ◽  
Theoretical Analysis ◽  
Load Capacity ◽  
Surface Curvature ◽  
Squeeze Film ◽  
Rectangular Plates ◽  
Capacity Curves ◽  
Pressure Distributions ◽  
Effect Of Surface

A theoretical analysis is made of the normal approach of flat and curved rectangular plates which are separated by a thin film of lubricant. Load capacity curves are presented and some typical pressure distributions are shown. The effect of surface curvature on the squeeze film generation is investigated.

Squeeze Film Characteristics of Circular Contacts at Constant Squeeze Velocity Motion with Non-Newtonian Lubricants

2011 ◽  
Vol 63-64 ◽  
pp. 147-151
Author(s):  
Li Ming Chu ◽  
Wang Long Li ◽  
Hsiang Chen Hsu
Keyword(s):  
Closed Form ◽  
Numerical Solutions ◽  
Hydrodynamic Lubrication ◽  
Closed Form Solution ◽  
Elastohydrodynamic Lubrication ◽  
Form Solution ◽  
Squeeze Film ◽  
High Pressure Stage ◽  
Time Calculation ◽  
Film Characteristics

In this paper, the numerical solutions in pure squeeze motion are explored by using hydrodynamic lubrication (HL) and elastohydrodynamic lubrication (EHL) models at constant squeeze velocity with power law lubricants. This paper also proposes a closed form solution to calculate the relationship between central pressure and central film thickness under HL condition. In order to save time calculation, the present closed form solution can be used as the initial condition for analysis of EHL at the high-pressure stage. In addition, this paper also discussed the HL and EHL squeeze film characteristics.

Squeeze film behavior in porous transversely circular stepped plates with a couple stress fluid

2016 ◽  
Vol 33 (2) ◽  
Author(s):  
Santhana Krishnan Narayanan ◽  
A Chamkha ◽  
Sundarammal Kesavan
Keyword(s):  
Surface Roughness ◽  
Couple Stress ◽  
Design Methodology ◽  
Reynolds Equation ◽  
Closed Form Solution ◽  
Stochastic Theory ◽  
Classical Case ◽  
Form Solution ◽  
Couple Stress Fluid ◽  
Squeeze Film

Purpose The purpose of this work is to carry our a study of the effect of surface roughness on squeeze film behavior between two transversely circular stepped plates with couple stress lubricant when the upper circular stepped plate has porous facing which approaches the lower plate with uniform velocity. Design/methodology/approach The modified Stochastic Reynolds equation is derived for Christensen Stochastic theory for the rough surfaces. Closed form solution of the Stochastic Reynolds equation is obtained in terms of Fourier-Bessel series. Findings It is found that the effect of couple stress fluid and surface roughness is more pronounced compared to classical case. Originality/value The problem is original that it consider a couple stress fluid in this type of applications.

Design of the Ball Screw Mechanism for Optimal Efficiency

1989 ◽  
Author(s):  
M.-C. Lin ◽  
S. A. Velinsky ◽  
B. Ravani
Keyword(s):  
Closed Form ◽  
Static Analysis ◽  
Load Capacity ◽  
Equations Of Motion ◽  
Closed Form Solution ◽  
Form Solution ◽  
Ball Screw ◽  
Exact Theory ◽  
Screw Mechanism ◽  
Extensive Computation

Abstract This paper develops theories for evaluating the efficiency of the ball screw mechanism and additionally, for designing this mechanism. Initially, a quasi-static analysis, which is similar to that of the early work in this area, is employed to evaluate efficiency. Dynamic forces, which are neglected by the quasi-static analysis, will have an effect on efficiency. Thus, an exact theory based on the simultaneous solution of both the Newton-Euler equations of motion and the relevant kinematic equations is employed to determine mechanism efficiency, as well as the steady-state motion of all components within the ball screw. However, the development of design methods based on this exact theory is difficult due to the extensive computation necessary and thus, an approximate closed-form representation, that still accounts for the ball screw dynamics, is derived. The validity of this closed-form solution is proven and it is then used in developing an optimum design methodology for the ball screw mechanism based on efficiency. Additionally, the self-braking condition is examined, as are load capacity considerations.

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