颗粒碰撞率的实验研究

EXPERIMENTAL INVESTIGATION OF INTER-PARTICLE COLLISION RATE

本文采用一种新的研究思路,以高速摄像作为手段,结合各种新颖的PTV算法,在毫秒级时间尺度和毫米级空间尺度上(颗粒尺寸)来对颗粒碰撞率做实验研究,对长期以来一直沿用的描述颗粒碰撞率的关系进行检验与修正。通过对实际颗粒碰撞率与颗粒浓度、平均相对速度的关系进行测量研究,发现理论关系与实验存在较大的差别,理论关系较大地高估了碰撞率。指出了需要进一步深入和完善描述颗粒碰撞率的实验规律,这些规律可直接应用于气固两相流动的数值计算与理论分析中。

A new approach, including high-speed photograph combined with various advanced PTV algorithms, was introduced to make experimental investigations on inter-particle collision rate on time scale of millisecond and space scale of millimeter. These experimental data is necessary to validate and correct the commonly used theoretical expressions of collision rate. The collision rate, particle concentration and average relative velocities of real particulate flow were investigated and it is shown that theoretical expressions much overestimate inter-particle collision rate. The necessity and significance were pointed for the further experiments on inter-particle collision expressions, which can be applied in simulation and analysis of gas-solid two-phase flow.