高压环境下水滴碰撞动力学研究

A droplet collision experimental system was established considering the real environment in an engine combustion chamber. The combination of a high-speed camera with a telephoto microscope lens was used to capture the droplet collision process under high ambient pressure for the first time, and high-resolution droplet collision images using water as the medium were obtained. Based on the captured images, a set of data processing methods was developed to quantify the collision Weber number We and collision parameter B, then the processed data was plotted on a We-B nomograph for analyzing. It is found that when the environmental pressure is low, there are coalescence, stretching separation, and reflective separation results as the collision Weber number and collision parameters change. However, when the ambient pressure gradually increases, the water droplets appear to “bouncing off” after collision. Subsequently, the shape factor of the droplet after collision was corrected, and the influence of environmental pressure was taken into account referring to the analysis of droplet collision boundary by Estrade et al. Finally, the boundary between coalescence and bouncing under different environmental pressures was obtained, achieving a high degree of agreement with experimental data.