Effect of Surface Roughness and Couple Stresses on Squeeze Films between Curved Annular Plates

Abstract

The combined effects of couple stresses and surface roughness patterns on the squeeze film characteristics of curved annular plates are studied. The Stokes (1966) couple stress fluid model is included to account for the couple stresses arising due to the presence of microstructure additives in the lubricant. In the context of Christensen's (1969) stochastic theory for the lubrication of rough surfaces, two types of one-dimensional roughness patterns (circumferential and radial) are considered. The governing modified stochastic Reynolds type equations are derived for these roughness patterns. Expressions for the mean squeeze film characteristics are obtained. Numerical computations of the results show that the circumferential roughness pattern on the curved annular plate results in more pressure buildup whereas performance of the squeeze film suffers due to the radial roughness pattern for both concave and convex pads. Further the squeeze film time is longer (shorter) for the circumferential (radial) roughness patterns. Improved squeeze film characteristics are predicted for the couple stress lubricant.

Ferrofluid-based annular squeeze film bearing with the effects of roughness and micromodel patterns of porous structures

“…An exact solution, valid for arbitrary wall thickness was given for the film pressure and pressure in the bearing material. Recently, many authors [17][18][19] have tried couple-stress fluid as lubricant with the effect of surface roughness in the analysis of squeeze film bearings. Theory of couple-stress fluids [20] is the simplest generalization of classical theory of fluids which account for polar effects such as the presence of anti-symmetrical stresses, couple-stresses and body couples.…”

“…It was shown that the effect of magnetic field increased the mean load-carrying capacity and lengthens the mean squeeze time. Basti [19] discussed effect of surface roughness on squeeze film between curved annular plates using couple-stress fluid. It was shown that the circumferential roughness pattern on the curved annular plate results in more pressure buildup, whereas performance of the squeeze film suffers due to the radial roughness pattern for both concave and convex plates.…”

Combined effect of circumferential roughness and squeeze velocity on ferrofluid squeeze film with rotating sphere and rough plate

“…As a result, they found that circumferential roughness increased load capacity and mean response time, however, these trends are reversed for the radial roughness pattern. Basti 9 studied the effects of radial and circumferential surface roughness in the presence of curved annular plates, and found that the circumferential roughness leads to more pressure built up, while radial roughness affects both concave and convex plates resulting in different squeeze film behavior. Naduvinamani et al 10 investigated squeeze film lubrication between sphere and plate, and they found that load-carrying capacity and squeeze time increased for azimuthal roughness pattern.…”

Theoretical study of Shliomis model based magnetic squeeze film in rough curved annular plates with assorted porous structures

“…[2] analyzed the behaviour of a magnetic fluid based squeeze film between rotating transversely rough porous annular plates incorporating elastic deformation. [3] examined the combined effect of couple stresses and surface roughness patterns on the squeeze film characteristics of curved annular plates.…”