Analysis of the flow rate through rotating shafts in lubricating circuits

The paper presents the CFD simulation of the oil flow distribution in a rotating system. The aim of the study is to validate the modelling approach for applications in dimensioning and analysing lubrication circuits. A specific experimental assembly was manufactured for measuring the flow rate distribution in a rotating shaft enclosed in a liner with axial inlet and three radial outlets. The flow rate of each outlet was measured by a dedicated turbine flow meter. It was found that, except for high fluid viscosities, the flow rate through the farthest outlet is the highest, due to the inertia of the oil that tends to flow straight on until the last outlet, despite the longest distance, instead of leaving the axial channel through the first radial holes. The angular speed has a slight effect in increasing the nonuniform flow distribution and a significant influence in decreasing the feed pressure. It has been demonstrated that the simulated results are reliable, and the methodology can be used for designing properly the circuit layout in order to obtain a homogeneous flow distribution.