# Calculation method of impingement depth and multiple objective optimizations of nozzle layout for aviation gears considering windage

## TL;DR

This paper proposes a method to calculate windage impingement depth and optimize nozzle layouts for aviation gears to improve lubrication efficiency.

## Contribution

A novel analytical model and multi-objective optimization method for oil jet layout in high-speed aviation gears is introduced.

## Key findings

- Modulus and transmission ratio positively correlate with oil jet streamline offset range.
- Inclination angle and initial offset negatively correlate with impingement depth of two gears.
- Optimized parameters reduced impingement depth difference by over 50.3% and align with CFD results.

## Abstract

As the rotating speed of aviation gears becomes higher and higher, the influence of windage resistance on jet streamline must be considered in lubrication system design. To provide theoretical guidance for nozzle layout, an analytical model to calculate the windage impingement depth of gears is proposed. To obtain the best oil jet lubrication effect, the multi-objective optimization design method of oil jet streamline layout parameters with the largest impingement depth and the smallest impingement depth difference between two gears was proposed. CFD simulation analysis of flow field around gears are conducted to study the influence of jet nozzle layout parameters on the oil distribution and oil pressure. The results show that: the modulus and transmission ratio mainly affect the value range of oil jet streamline offset, and the correlation is positive. With the increase of inclination angle and initial offset, the impingement depth of the two gears is negatively correlated. The optimized oil jet streamline layout parameters of the case in the article are S = 0.53 mm, β = 4.6°, and the impingement depth difference between the two wheels of the gear pair after optimization is reduced by more than 50.3%. Calculation results are consistent with CFD, which validates the effectiveness and accuracy of the model. This research provides a design theory and method for the selection of oil lubrication parameters for aviation high-speed and heavy-load aviation gears.