Investigation on Dynamic and Transient Thermal Characteristics of High-Speed and High-Power-Density Dry Friction Clutch in STOVL Aircrafts

As a critical core component in the STOVL aircrafts, the dynamic and thermal performance of the aviation dry clutch directly determines the reliability of power transmission and the precision control, especially in high relative speed engagement and high power density conditions. Accordingly, this study proposes a 4-DOF dynamic model considering the time-varying of friction coefficient and nonlinear load characteristics, integrated with a transient thermal model incorporating the time-varying thermal parameters. The effects of pressure loading strategies and rotation speed on the dynamic and transient thermal responses are systematically analyzed. Furthermore, a novel temperature uniformity coefficient is developed to characterize the temperature field distribution. The results indicate that the pressure loading strategy fundamentally dictates the trade-off between engagement smoothness and thermal performance. Specifically, compared with other loading strategies, the linear loading strategy yields the most uniform thermal field (UTz=0.4361, UTr=0.3971) and the engagement smoothness (Jer=2.353×105rad·s−3) but increases sliding friction work (163.67 kJ). As rotation speed increases from 1500 r/min to 6000 r/min, the sliding friction work increases from 8.85 kJ to 163.67 kJ. Concurrently, the peak values of temperature, axial temperature gradient and axial temperature uniformity coefficient reach 116.557 °C, 80.622 °C and 0.4361, respectively. Consequently, an appropriate reduction in rotation speed combined with the adoption of linear loading strategy can not only facilitate the smoothness and friction loss reduction but also achieve a more uniform temperature distribution. These findings are not only essential for optimizing the thermal management and structural design of aviation dry clutches but also establish a quantitative basis for optimizing engagement strategies.