金属微粒与电极碰撞恢复系数的理论和实验研究

金属微粒是降低气体绝缘金属封闭输电线路(GIL,gas insulated transmission lines)绝缘强度的关键因素之一,研究金属微粒与电极的碰撞恢复系数可为微粒陷阱等金属微粒抑制措施提供理论基础。基于弹塑性变形理论,给出了法向恢复系数和切向恢复系数计算公式,并通过碰撞恢复系数测量平台研究了微粒材质特性、微粒直径以及碰撞速度对碰撞恢复系数的影响规律,实验测量结果验证了理论计算公式的可靠性。理论计算和实验测量表明:按金属材质铝、铜、钢的顺序,法向碰撞恢复系数逐渐减小,切向碰撞恢复系数逐渐增大;法向碰撞恢复系数和切向碰撞恢复系数均与微粒直径呈负相关;同一斜碰撞角度下,法向碰撞恢复系数随碰撞速度的增加而减小,切向碰撞恢复系数随碰撞速度的增加先减小后增加,并且不同斜碰撞角度下的法向碰撞恢复系数或切向碰撞恢复系数变化规律类似。文中关于碰撞恢复系数的计算方法可为微粒陷阱等工程设计提供理论支撑。

Theoretical and experimental study on impact recovery coefficient of metal particles and electrodes

Metal particles are one of the key factors in the insulation strength reduction of gas insulated transmission lines (GIL). The study of the impact recovery coefficient of metal particles and electrodes can provide a theoretical basis for the suppression of metal particles. Based on the elastoplastic deformation theory, the formula of the normal recovery coefficient and the tangential recovery coefficient were derived in this work. The effects of particle material properties, particle diameter and collision velocity on the impact recovery coefficient were studied by the collision recovery coefficient measurement platform. The experimental results verify the reliability of the theoretical calculation formula. The theoretical calculations and experimental measurements show that according to the order of metal aluminum, copper and steel, the normal impact recovery coefficient gradually decreases, while the tangential impact recovery coefficient gradually increases. Both the normal impact recovery coefficient and the tangential impact recovery coefficient are negatively correlated with the particle diameter. Besides, under the same oblique impact angle, the normal impact recovery coefficient decreases with the increase of the collision velocity, but the tangential impact recovery coefficient decreases first and then increases with the increase of collision velocity, and the variations of normal or tangential restitution coefficients under different oblique impact angles are similar. The calculation method of collision recovery coefficient can provide theoretical support for engineering design of particle traps.