This study investigates the flow field and temperature field characteristics of a certain type of aerospace tail-thrust clutch friction plate under engagement conditions. A thermo–fluid–solid coupled convective heat transfer model was established based on the velocity distribution of lubricating oil within the groove cavities. The model was applied to analyze the surface temperature distribution of a single friction pair (friction plate and steel plate) under different operating parameters. The results reveal that both the inlet temperature and flow rate of the lubricating oil have a mitigating effect on temperature rise. However, due to the geometric constraints of the groove structure, the maximum wetted area and the actual inflow are inherently limited. Consequently, the temperature evolution during engagement is more significantly influenced by rotational speed and applied pressure. In particular, once these parameters exceed certain critical values, the surface temperature exhibits a sharp increase. Furthermore, the optimization of lubricating flow is constrained by friction materials. A higher flow rate does not necessarily yield greater lubrication benefits; instead, the optimal flow rate solution tailored to the friction pair should be pursued. This work provides theoretical insights into parameter control for aerospace tail-thrust clutches in practical operation.

Tapered roller bearings are extensively utilized in the aerospace industry owing to their superior load-carrying capacity and extended service life. However, the majority of research conducted by scholars on the subject of bearing lubrication has focused on ball and cylindrical roller bearings. There is a paucity of research on the internal lubricants and air distribution of tapered roller bearings under oil jet lubrication conditions. This paper presents a computational fluid dynamics (CFD) simulation model specifically designed for the oil jet lubrication of tapered roller bearings. The flow field inside the bearing cavity is analyzed under various operating conditions, and the impact of different parameters on lubrication performance is quantitatively assessed using the oil return efficiency as a metric. Additionally, an experimental test stand for the jet lubrication of tapered roller bearings was developed. The simulated oil return efficiency was compared with experimental data, revealing discrepancies within 10%, thereby validating the accuracy of the CFD model. The findings suggest that directing the oil jet toward the smaller end of the bearing, appropriately increasing the nozzle flow rate, and utilizing positive jetting can significantly improve the lubrication performance of tapered roller bearings.

In aeronautic industry applications, multi-branch oil jet nozzles are commonly employed to supply lubricating oil, ensuring adequate thermal regulation and friction control for high-speed gears or bearings. The geometric and operational parameters of these nozzles significantly affect the internal flow dynamics and discharge coefficient characteristics. This study presents a numerical investigation into the flow behavior and discharge coefficient of multi-branch oil jet nozzles under typical pressure conditions (0–0.5 MPa) for various orifice sizes and angles. Then, compared to the original theoretical method, the pressure correction equation leveraging the fitting curve method is determined to improve the prediction accuracy of the theoretical method of oil mass flow rate and enhanced by over an order of magnitude. Furthermore, the flow behavior and mass flow properties of multi-branch nozzles, featuring various configurations and distinct orifice angles, are also investigated amply by comparing the numerical and theoretical findings.

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.