Abstract: Wet particulate matter widely exists in nature, production and daily life. Surface Evolver was used to investigate the shape of liquid bridge between two ellipsoidal wet particles placed vertically and parallel to each other during the relative rotation and the effects of contact angle, rotation angle, gravity and other parameters were analyzed. Under several different contact angles, the changes in the relative angle between the two particles from 0° to 90° were observed to analyze the changes in the gas-liquid surface area, solid-liquid contact area, and the shape of the contour line obtained by intersecting the plane passing through the center line of the two particles with the surface of the liquid bridge. The differences in the contour line shape of the liquid bridge under the same relative angle with and without gravity were compared. The results showed that the shape of the liquid bridge was a rotationally symmetric body. This body did not satisfy the arc assumption. The variation of the contact angle changed the shape of the liquid bridge. The changes in rotation angle and gravity caused the profile of the liquid bridge to change. Specifically, it changed from an elliptic curve to a hyperbola. The gravity caused the contact line on the upper and lower particles to shift. The rotation of the particles resulted in the reduction of the solid-liquid interface. The gas-liquid interface area of the liquid bridge was sinusoidally related to the relative angle of the particles. The minimum volume required to maintain the liquid bridge under gravity was investigated by gradually reducing the volume of the liquid bridge, and it was shown to be quadratically related to the contact angle and to increase with the increase in liquid density, with the minimum volume required to maintain the liquid bridge when the contact angle was about 90°.

Key words: liquid bridge, ellipsoidal particle, shape of gas-liquid interface, Surface Evolver, rotation

摘要： 湿颗粒物质广泛地存在于自然以及生产生活中。针对两垂直平行放置的椭球形湿颗粒相对旋转过程中形成的中心液桥，采用Surface Evolver软件对其形状展开研究，分析了接触角、旋转角度、重力等参数的影响。结果表明，液桥形状是一个非圆弧假设的旋转对称体，接触角变化会改变液桥形状，旋转角度、重力均使得液桥中心垂直截面轮廓线从椭圆线向双曲线转变，重力使得上下颗粒上的接触线发生移动，而颗粒旋转会导致接触线收缩；液桥气液界面面积与颗粒相对角度呈正弦函数关系。对重力下维持液桥所需的最小体积进行了研究，表明其与接触角呈二次函数关系，并随着液体密度增大而增大，而且接触角90°左右时维持液桥所需体积最小。

关键词: 液桥, 椭球形颗粒, 气液界面形状, Surface Evolver, 旋转