Generalized ferrofluid based lubrication equation and its application to porous journal bearing

Abstract

This paper derived generalized ferrofluid based lubrication equation (based on the Shliomis model) from the basic theory for variable as well as uniform (transverse) strong magnetic fields. The variable magnetic field (VMF) is used because of retaining contributions from all magnetic terms of the Shliomis model. Moreover, it has an added advantage of generating maximum field at the required active contact zone in the bearing design system. Using above equation for variable and strong magnetic field, the case of porous journal bearing (PJB) is studied by considering equation of continuity in the film as well as porous region. The validity of the Darcy's law is assumed in the porous region. The modified Reynolds‐Darcy equation for PJB is derived by considering the effects of squeeze velocity, anisotropic permeability and slip velocity. The results show that dimensionless load‐carrying capacity increases with the increase of eccentricity ratio and the effect of magnetic field, and performed best for the decreasing values of the dimensionless permeability parameter in the x‐direction for a thin layer of the porous region. Moreover, the results are also compared with the behavior of different types of journal bearing designs discussed by different authors.

Lubrication impact of ferrofluid on cylinder‐plate system: A comparative study using two flow models

“…The right‐hand side of Equation () indicates the squeeze action on the lubricant film. The results for dimensionless film‐pressure P , load‐carrying capacity and time‐height relation are computed using Equations (), () and (), respectively, for representative value of the different parameters 5,12 given in Table 1 under the conditions …”

“…Ferrofluids (FFs) 1 are stable colloidal magnetic suspension of single domain ferromagnetic nanoparticles suspended in an appropriate carrier liquid, where particles are coated with surfactant to prevent its agglomeration. Mainly, three different types of FF models are discussed by different authors 2–6 : Neuringer–Rosensweig (NR), Shliomis and Jenkins. NR 1 proposed system of FF equations, where main feature is the consideration of the magnetic body force when an external magnetic field H is applied.…”

“…Some experimental results are also discussed. Shah and Shah 5 derived generalised FF based lubrication equation using transverse and variable magnetic fields. The case of porous journal bearing is studied using variable magnetic field (VMF) model.…”

Ferro‐elastohydrodynamic lubrication of inclined slider‐bearing

“…The results for the dimensionless load‐carrying capacity $$\bar{W}$$ are computed using Equation () for representative value of the different parameters (refer [12, 13]) given in Table 1. These values remain fixed throughout the calculation.…”

“…Assuming steady flow, neglecting inertia, and the second derivative of the internal angular momentum S, the basic FF flow equations governed by Shliomis model (referring [2,13,17]) are as follows.…”