The capture mechanism of fibrous filters in a wet condition is studied by focusing on the single droplet impact to an initial droplet attached to the fiber. High-speed photography and numerical simulation are conducted to study the collision phenomenon. The eccentricity between the mass center of the impacting droplet and the initial droplet is varied to evaluate the threshold capture velocity of the impacting droplet. The eccentricity is considered to be composed of two perpendicular components. The distance between the impacting droplet trajectory line and fiber axis is considered as one of the components of eccentricity (\(e_{1}\)). The distance between the mass center of the impacting droplet and the initial droplet along the fiber axis is defined as the other component of eccentricity (\(e_{2}\)). The initial droplet volume is also varied in our investigation. It is observed that increasing the initial droplet volume attached to the fiber as well as increasing the eccentricity \(e_{1}\) reduces the threshold capture velocity of the impacting droplet. However, increasing \(e_{2}\) increases the threshold capture velocity. Surprisingly, for an impacting droplet with a radius of R colliding with a small volume initial droplet of a radius of \(R_{i}\) at \(e_{2}> 0.85\) (\(R+R_{i}\)), the threshold capture velocity is found to be higher than that of a droplet impacting on a dry fiber.

通过关注单个液滴对附着在纤维上的初始液滴的撞击，研究了在潮湿条件下纤维过滤器的捕获机理。进行高速摄影和数值模拟以研究碰撞现象。改变撞击液滴的质心与初始液滴之间的偏心率，以评估撞击液滴的阈值捕获速度。偏心率被认为由两个垂直分量组成。撞击的液滴轨迹线与纤维轴之间的距离被认为是偏心率（\（e_ {1} \））之一。撞击液滴的质心与初始液滴之间沿纤维轴的距离定义为偏心率的其他分量（\（e_ {2} \））。在我们的研究中，初始液滴体积也有所不同。可以看出，增加附着在纤维上的初始液滴体积以及增加偏心率\（e_ {1} \）会降低撞击液滴的阈值捕获速度。但是，增加\（e_ {2} \）会增加阈值捕获速度。令人惊讶地，对于半径为R的撞击液滴与半径为\（R_ {i} \）的小体积初始液滴在\（e_ {2}> 0.85 \）（\（R + R_ {i} \）），发现阈值捕获速度高于液滴撞击干纤维的速度。