Pressure distribution in a porous squeeze film bearing lubricated by a Vočadlo fluid (original) (raw)
Related papers
Curvilinear Squeeze Film Bearing with Porous Wall Lubricated by a Rabinowitsch Fluid
International Journal of Applied Mechanics and Engineering, 2017
The present theoretical analysis is to investigate the effect of non-Newtonian lubricant modelled by a Rabinowitsch fluid on the performance of a curvilinear squeeze film bearing with one porous wall. The equations of motion of a Rabinowitsch fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and in a porous layer using the Morgan-Cameron approximation the modified Reynolds equation is obtained. The analytical solution of this equation for the case of a squeeze film bearing is presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. Thrust radial bearing and spherical bearing with a squeeze film are considered as numerical examples.
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2018
In this study, the effect of viscosity variation of non-Newtonian lubrication on squeeze film characteristics with porous and Rabinowitsch fluid for conical bearings is analyzed. The modified Reynolds equation representing the characteristics of non-Newtonian fluid with viscosity variation on the porous wall followed by the cubic stress law condition is invoked. For lubricant flow in a bearing clearance and in a porous layer Morgan–Cameron approximation is considered. A small perturbation technique is used to compute the pressure generation using modified Reynolds equation of lubrication. Approximate analytical solutions have been obtained for the squeeze film pressure, load-carrying capacity, squeeze film time, and center of pressure. The outcomes are displayed in diagrams and tables, which show that the effect of viscosity variation and porous wall on the squeeze film lubrication of conical bearings decreases film pressure, load-carrying capacity, and response time for the Newtoni...
Porous Squeeze Film Bearing with Rough Surfaces Lubricated by a Bingham Fluid
International Journal of Applied Mechanics and Engineering, 2014
In the paper the effect of both bearing surfaces and the porosity of one bearing surface on the pressure distribution and load-carrying capacity of a squeeze film bearing is discussed. The equations of motion of a Bingham fluid in a bearing clearance and in a porous layer are presented. Using the Morgan-Cameron approximation and Christensen theory of rough lubrication the modified Reynolds equation is obtained. The analytical solutions of this equation for a squeeze film bearing are presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. A thrust radial bearing is considered as a numerical example.
Curvilinear Squeeze Film Bearing Lubricated with a Dehaven Fluid or with Similar Fluids
International Journal of Applied Mechanics and Engineering, 2017
In the paper, the model of a DeHaven fluid and some other models of non-Newtonian fluids, in which the shear strain rates are known functions of the powers of shear stresses, are considered. It was demonstrated that these models for small values of material constants can be presented in a form similar to the form of a DeHaven fluid. This common form, called a unified model of the DeHaven fluid, was used to consider a curvilinear squeeze film bearing. The equations of motion of the unified model, given in a specific coordinate system are used to derive the Reynolds equation. The solution to the Reynolds equation is obtained by a method of successive approximations. As a result one obtains formulae expressing the pressure distribution and load-carrying capacity. The numerical examples of flows of the unified DeHaven fluid in gaps of two simple squeeze film bearings are presented.
International Journal of Applied Mechanics and Engineering, 2016
In this paper, the solution to a problem of pressure distribution in a curvilinear squeeze film spherical bearing is considered. The equations of motion of an Ellis pseudo-plastic fluid are presented. Using Christensen’s stochastic model of rough surfaces, different forms of Reynolds equation for various types of surface roughness pattern are obtained. The analytical solutions of these equations for the cases of externally pressurized bearing and squeeze film bearing are presented. Analytical solutions for the film pressure are found for the longitudinal and circumferential roughness patterns. As a result the formulae expressing pressure distribution in the clearance of bearing lubricated by an Ellis fluid was obtained. The numerical considerations for a spherical bearing are given in detail.
Squeeze-film flow of a viscoelastic fluid a lubrication model
Journal of Non-Newtonian Fluid Mechanics, 1988
In this paper the constant-speed squeezing flow of a model viscoelastic fluid which allows for a Carreau-type viscosity and a stress overshoot in a start up of a shear flow is considered. Based on the knowledge of the full numerical solution by a Boundary Element method a set of lubrication equations is constructed which we believe to retain all the essential physics. The lubrication equations consist of four partial differential equations in time and one spatial coordinate. These are more tractable than the full set of governing equations (partial differential equations in time and two spatial coordinates). The lubrication equations are solved by a Finite Difference scheme, and the results are compared favourably with the full numerical solutions. The mechanism for load enhancement is also discussed.
Effect of concentration dependence of viscosity on squeeze film lubrication
Zeitschrift für Naturforschung A, 2020
The influence of concentration of solute particles on squeeze film lubrication between two poroelastic surfaces has been analyzed using a mathematical model. Newtonian viscous fluid is considered as a lubricant whose viscosity varies linearly with concentration of suspended solute particles. Convection-diffusion model is proposed to study the concentration of solute particles and is solved using finite difference method of Crank–Nicolson scheme. An iterative procedure is used to get the solution for concentration, pressure and velocity components in film region. It has been observed that load carrying capacity decreases as the concentration of solute particles in the fluid film decreases. Further, the concentration of suspended solute particles decreases as the permeability of the poroelastic plate increases and these results may be useful in understanding the mechanism of human joint.
International Journal of Pure and Apllied Mathematics
On the basis of the micro continuum theory, a theoretical analysis of the effects of pressure distribution using couple stress on the squeeze film behavior of parabolic inclined slider bearing is presented. The modified Reynolds equation governing the squeeze film pressure is derived by using the stokes constitutive equation and the analysis taking into account the squeezing effect with no slip at the porous interface comparing with the traditional Newtonian lubricant case, the effects of couple stress characteristics by the couple stress parameter signify an improvement in the steady state performance. We are considering the parabolic inclined bearing to analyze the effect of pressure and compared to the inclined plane bearing, step inclined bearing, the parabolic shaped slider bearing lubricated with couple stress fluids results in a higher pressure distribution. The performances are emphasized especially for the bearing with smaller film heights.
Acta Polytechnica, 2023
In recent years, there has been much interest in the effects of porosity and surface roughness (SR) or geometric irregularities between two moving plates under hydrodynamic lubrication. Porous bearings are used extensively in wide range of equipment, including computers, office equipment, home appliances, electric motors, and vehicles. In light of the importance of the aforementioned applications, we explored how SR and porous materials affect annular discs under the condition of a squeeze film. A five-point Gauss quadrature integral formula has been used to examine the characteristics of annular discs and a small perturbation method has been used to discretise the governing Rabinowitsch fluid flow (RFF) equations. The impact of nonlinear parameters on the behaviour of porosity and SR have been visualised in terms of film pressure (FP), load carrying capacity (LCC), and squeeze response time (SRT) of annular discs. Under the conditions of pseudoplastic and dilatant fluids, the effects of SR and porous materials between annular discs have been estimated in the form of the film pressure, LCC, and SRT and are presented in this manuscript as tables and graphs. According to the findings, the performance of an annular disc is significantly affected by porous material and radial roughness patterns. In addition, when RFF is carried through a rough surface and porous media, the performance is found to improve for dilatant fluids but suffer for pseudoplastic fluids.
Analysis of Squeeze Films Between Rough Circular Plates Lubricated with Rabinowitsch Fluids
American Journal of Mechanics and Applications, 2019
The present theoretical work investigates the combined impacts of non-Newtonian (pseudoplastic and dilatant) lubricants and surface roughness on the performance of squeeze films lubrication between two rough circular plates. The modified Reynolds equation has been derived on the basis of Christensen's stochastic theory of hydrodynamic lubrication for rough surfaces. The lubricant model adopted for the analysis is Rabinowitsch fluid model-an experimentally verified fluid model for lubricated bearing systems. Two types of one-dimensional roughness patterns (radial and azimuthal) have been considered in the analysis. An asymptotic solution for squeeze film pressure, load carrying capacity and squeeze film time are obtained. The numerical results for dimensionless film pressure, load carrying capacity and film squeezing time have been calculated for various values of fluid and operating parameters. The results for dimensionless film pressure, load capacity and squeezing time of the lubricant film have been discussed with clear graphical presentation for different values of parameters of pseudoplasticity and roughness. It was observed that the radial roughness decreases the film pressure, load capacity and squeezing time of lubricant, while increased values of these properties were observed for azimuthal roughness. It was also observed that the pseudoplastic lubricants decrease the film pressure and load capacity, while the dilatant lubricants increase these properties. Also, the variations in these results are highly significant.