Research and Optimization of Flow Characteristics in a Two-Stage Centrifugal Oil Supply Structure for Wet Clutches

In the tail rotor transmission system of a high-speed helicopter, the timely supply of lubricating oil to the wet friction clutch during frequent starts and stops has a significant impact on the performance of the transmission system. The oil flow requirements of clutches vary across different operational stages, posing a challenge for traditional centrifugal oil supply methods to meet the demand for flow regulation under such dynamic conditions. This paper proposes a novel two-stage centrifugal oil supply structure capable of achieving superior flow control during various clutch operating phases. An experimentally validated two-phase oil–gas CFD model was established to analyze the effects of operational parameters, such as rotational speed and oil supply pressure difference, as well as structural parameters, on oil supply performance. To enhance oil supply flow rate and efficiency under high-speed conditions (rated speed of 4800 rpm and 85% speed) at a common supply pressure (0.45 MPa), while reducing the pressure at the input shaft interface, key structural parameters were determined and optimized using a combined approach of Taguchi orthogonal experiments and response surface methodology. The results demonstrate that the optimized structure achieves a 142.8% increase in the weighted oil supply flow rate, an 11.1% improvement in oil supply efficiency, and a 7.5% reduction in pressure at the input shaft interface.