Lubrication effects on axisymmetric flow of a micropolar fluid by a spiraling disk

Abstract

Advances in modern technology and extremely stringent demands for rotating elements of machines impose researchers on the need for the continuous development of improved lubricants to ensure the stability, safe operation, and reliability of various bearings. For operations at high speed and heavy load, modern bearings use lubricants containing high molecular weight polymer components. Such lubricants exhibit non-Newtonian rheological behavior. Power-law lubricant is widely used for the bearings and the industrial lubrication processes. This article is established to estimate the power-law lubrication effects on the Homann flow of a micropolar fluid past a disk with the spiraling motion. A lubrication layer of a non-Newtonian power-law lubricant with negligible thickness is applied between the disk rough surface and the bulk fluid. A new and very complex interfacial boundary condition is derived for the lubricated spiraling disk and is utilized to explore the impact of different flow parameters on the fluid velocity as well as the microrotation. Numerical results are computed for some quantities of physical interest, i.e., radial, azimuthal skin friction coefficients, and the wall shear stress are calculated for various values of the spiral angle, disk spiraling parameter, material parameter, and slip parameter. The addition of slip assists the radial velocity and opposes the azimuthal velocity. The radial velocity is enhanced by increasing the disk spiraling and spiral angle.