Fluid Dynamic Loss Model with Wide Applicability for Aeroengine Transmission Gears

Abstract In high-speed gear systems for aeroengines, it is important to reduce the fluid dynamic loss, which accounts for the majority of power loss, to improve the fuel efficiency. For reasonable loss-reduction and the standardization of low-power-loss designs, a fluid dynamic loss model with wide applicability is needed. However, there are few reports of loss models considering the gear shroud effect on the oil dynamic loss. This study developed a loss model based on fluid dynamic loss phenomena. Specifically, fluid dynamic loss models were developed for the "air side-flow loss," "air pumping loss," "oil-jet acceleration loss," and "oil re-acceleration loss" in the gear meshing part, and "air vortex loss" and "oil churning loss" in the gear peripheral part, with consideration to the shrouding effect. Moreover, an experimental method and a numerical method for loss classification are proposed. The fluid dynamic loss models were validated by experiments or experimentally validated numerical simulations. To demonstrate the effectiveness of the loss model for low-power-loss design, the influence of the design parameters was investigated, and the typical parameters were optimized.