Squeeze film characteristics of parallel circular disks lubricated by ferrofluids with non-Newtonian couple stresses

In the present theoretical investigation, the effect of ferrofluid on the dynamic characteristics of curved slider bearings is presented using Shliomis model which accounts for the rotation of magnetic particles, their magnetic moments, and the volume concentration in the fluid. The modified Reynolds equation for the dynamic state of the bearing is obtained. The results of dynamic stiffness and damping characteristics are presented. It is observed that the effect of rotation of magnetic particles improves the stiffness and damping capacities of the bearings.

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Dynamic Performance Characteristics of a Curved Slider Bearing Operating with Ferrofluids

We make an effort to analyze the behavior of squeeze film characteristics of different finite plates with couple stress fluid in the presence of a transverse magnetic field. On the basis of the Stokes couple stress fluid model and hydromagnetic flow model, a modified Reynold's equation is derived, which is solved by using appropriate boundary conditions to obtain squeeze film pressure, load-carrying capacity, and squeeze film time. The graphical representation of the results suggests that the different bearing systems register an enhanced performance with couple stresses compared to that of a bearing system working with a conventional lubricant in the presence of a transverse magnetic field. It is observed that the effect of applied magnetic field on the squeeze film lubrication between different finite plates with conducting couple stress fluids is to increase the load-carrying capacity significantly and to delay the time of approach compared to the corresponding nonconducting Newtonian case. It is seen ...

Modified Reynolds Equation for Different Types of Finite Plates with the Combined Effect of MHD and Couple Stresses

Modelling and experimental study on the influence of surface grooves on near-field acoustic levitation

Effect of surface roughness on magnetohydrodynamic squeeze film characteristics between finite rectangular plates

The effect of surface roughness on squeeze film behavior between two circular disks with couple stress lubricant is analyzed when the upper disk has porous facing which approaches the lower disk with uniform velocity. The modified Stochastic Reynolds equation is derived on the basis of Stokes micro-continuum theory for couple stress fluid and Christensen Stochastic theory for the rough surface. Closed form solution of the Stochastic Reynolds equation is obtained in terms of Fourier–Bessel series. The importance of roughness and couple stress on bearing characteristics are presented in terms of load carrying capacity, squeeze time, and relative percentage of the load. It is observed that, effect of couple stress fluid, and surface roughness is more pronounced compared to classical case. These predictions enable design engineers to choose suitable parameters.

Surface roughness effects on squeeze film behavior in porous circular disks with couple stress fluid

Numerical solution of the MHD Reynolds equation for squeeze film lubrication between two parallel surfaces

This paper describes the combined effect of surface roughness and couple stress fluid on the performance characteristics of squeeze film lubrication between two circular plates. Using microcontinuum theory for the couple stress fluid and the Christensen stochastic model for the surface roughness, the modified Reynolds equation is derived by assuming the roughness asperity heights to be small compared to the film thickness. An eigenvalue problem involving Bessel functions enables analysis of the Reynolds equation. The expressions for mean pressure, load-carrying capacity, and squeeze film time are obtained for various probability distribution functions (pseudo normal, rectangular, and inverse square root distributions) that characterize the roughness of the lubricating surfaces. The influence of roughness and couple stress on bearing characteristics is presented in terms of the relative percentage in load for all these roughness patterns. Â© 2009 Begell House, Inc.

D. P. Basti

Papers

Surface roughness effects on squeeze film behavior in porous circular disks with couple stress fluid

Numerical solution of the MHD Reynolds equation for squeeze film lubrication between two parallel surfaces

Roughness effect on squeeze film characteristics of porous circular plates lubricated with couple stress fluid

Non-newtonian fluid model for pressure-driven flow between porous and rough surfaces in journal bearing