Development of a Viscosity Model and an Application, for the Filling Process Calculation in Visco-Dampers

Abstract

The lifetime and thermal management of torsional vibration dampers, working with silicone oils, begin at the design and development phases, of this damping product, with help of properly developed material and CFD simulation models. Dynamic viscosity measurements have been carried out on AK 1 000 000 STAB silicone oil samples, with a high-precision rotational rheometer, to quantify the temperature and shear rate dependence of the mentioned silicone oil’s non-Newtonian viscous behavior. Eight commonly used pseudoplastic non-Newtonian viscosity models have been selected for model parameter estimation and comparison, to develop a reliable, accurate and easy-to-implement viscosity model valid in -40°C-200°C temperature and 0 1/s-1000 1/s shear rate ranges, based on the expected operational range of the fluid. The filling process of an existing, small-sized torsional vibration damper has been thoroughly analyzed under eight different filling conditions and filling time comparison. Filling mass characteristics, maximal allowed oil inlet temperatures and maximal oil filling velocities have been determined for each case with help of 3D, transient, multiphase, coupled fluid dynamic and heat transfer calculations.