The efficient designs of lubrication and heat transfer in an aeroengine bearing chamber require a better understanding of the complex air/oil two-phase flow in the chamber, which contains oil droplet deformation and motion, as well as droplet/wall interactions including wall impingement and deposition behavior. A modified droplet deformation model is proposed to describe the effect of deformation on the motion, and then a splash critical criterion also is established by means of energy conservation to estimate the impingement conditions of droplets. Using the above knowledge, in combination with a secondary droplet characteristic model predicting the outcome of droplet impact with wall, the droplet deformation, motion, and the associated transfer of mass and momentum are calculated in an aeroengine bearing chamber, and the effects of air mass flow rates and shaft speeds are subsequently discussed. This article may contribute to providing initial conditions to study further film flow behavior on the chamber housing.

We propose a light-emitting diode headlamp for motorcycles based on freeform micro-lenses. The freeform micro-lenses include a collimator and micro-lens structures. The rays emitted by the light-emitting diode source are first collimated and then redistributed by the microstructures. We make a point by point relationship between the light-emitting diode source and the target plane according to Economic Commission for Europe Regulation R113 revision 2. Simulation results show that the light pattern of our proposed headlamp could satisfy the requirements of the regulation. Illuminance on the test points, lines, and zones can fully meet the Economic Commission for Europe Regulation. The optical efficiency of our proposed headlamp could reach up to 90%, which is much higher than the traditional design.