Flow Characteristics of Viscous Oil Film Between Large Diameter Rotating Disks

Based on the measured viscosity of YLA-N32 hydraulic oil, a viscosity-diameter expression, simple and suitable for the hydro-viscous drive (HVD) device, was deduced using polynomial fitting method. Taking account of the effect of pressure difference and inertia force on the oil film, the analytic solutions for pressure, radial velocity and flow rate with variable viscosity were derived. The results show that when the viscosity is constant, the pressure and radial velocity are approximately linear with the radius. Considering the viscosity-diameter relationship, the pressure and radial velocity are nonlinear with the radius, and the pressure is lower than that when viscosity is constant at the same radius. Inertia force makes the pressure of the rotating disk decrease. Compared with that caused by the inertia force, the radial velocity caused by the pressure difference is very small, even can be neglected. The formulas and conclusions obtained have significant theoretical and practical values.