Magneto-hydrodynamics of couple stress lubricants in combined squeeze and shear in parallel annular disc viscous coupling systems

Abstract

This paper presents predictive analysis of load carrying capacity, tractive efficiency and response time of parallel annular discs intervened with a film of lubricant under combined shear and squeeze film motions. This configuration represents operational characteristics of viscous coupling systems. In particular, the case of viscous dampers for tractive torque generation and distribution in all-wheel-drive off-road vehicles is studied. Various forms of lubricant behaviour, from idealised Newtonian to that of non-Newtonian silicone-based fluids and incompressible isothermal electrically conducting couple stress fluids, subjected to a magnetic field are studied (MHD). The solution for the MHD includes combined solution of modified Reynolds equation and Stoke's micro-continuum for couple stress fluids in squeeze and shear with rotational fluid inertia, an approach not hitherto reported in literature.It is shown that in general MHD couple stress fluids enhance the load carrying capacity of the contact and inhibit the incidence of thin films which can result in direct contact of surfaces. Rotational inertia decreases the load carrying capacity, although in general the MHD fluids show better load carrying capacity and tractive efficiency than the other alternatives. However, they exhibit a lower response time under the assumed isothermal condition. Nevertheless, the MHD fluids are best suited to applications in viscous coupling systems because of their controllability.

Influence of MHD Lubrication and Textured Surface in EHL Line Contact

“…As the value of "Hm" approaches zero, Equation (9) reduces to the Reynolds equation (i.e., non-conducting electrical lubricant), with lubricant considered to behave as Newtonian fluid. Table 2 presents operating parameters which have been selected from available literature (Lin et al, 2013;Daliri et al, 2015) for the present work. A steady state lubricant film pressure distribution is achieved by a coupled solution of different governing Equations (9, 12, 13, 14, and 16) satisfying the (a) Lubricant rheological properties (Lin, 2010;Daliri et al, 2015) Physical quantity Symbol Numerical value of physical quantity Dowson and Higginson (1966) and Hamrock and Jacobson (1984) Dimensionless load W 2×10 −5 − 7 × 10 −5…”

The Performance of Squeeze Film between Parallel Triangular Plates with a Ferro-Fluid Couple Stress Lubricant

“…Upper plate squeezing motion will lead to v � 0 at z � h and w � dh/dt. Equations (1) and (2) will lead to the velocity components of u and v under the boundary conditions described in (7) and 8:…”

“…ey also showed that magnetohydrodynamic couple stress fluids perform better in a steady load rather than a transient load conditions. For lubricated parallel annular discs, combined with squeeze film and shear motions, Daliri et al [7] showed that contact load-carrying capacity increases by the presence of magnetohydrodynamic couple stress fluids. For the same geometry of parallel annular plates, however, increased rotational inertia can diminish the squeeze film characteristics [8].…”

Investigation of Combined Effects of Rotational Inertia and Viscosity–Pressure Dependency on the Squeeze Film Characteristics of Parallel Annular Plates Lubricated by Couple Stress Fluid

“…Other studies in the field of couple stress lubricants can be found elsewhere [17][18][19][20]. Also, fluid flow in rotating discs has been investigated by other researchers [20][21][22][23][24][25][26]. However, according to the earlier studies reviewed above, investigation of squeeze film characteristics between two parallel annular discs considering effects of couple stress fluid and viscosity-pressure dependency together with considering rotational inertial effects have not been a topic of investigation.…”

“…Recently, Lin et al [16] studied the effects of viscositypressure dependency on the non-Newtonian squeeze film characteristics between parallel circular plates. Other studies in the field of couple stress lubricants can be found elsewhere [17][18][19][20]. Also, fluid flow in rotating discs has been investigated by other researchers [20][21][22][23][24][25][26].…”