直角凸壁面附近非对称位置的空泡动力学行为实验研究

ExperimentalStudy on the Dynamic Behavior of a Cavitation Bubble at the Asymmetric Position near a Right-Angled Convex Wall

空化破坏现象在核电厂中广泛存在。为了更深入地揭示空化破坏的机理,本文借助高速摄影实验系统,研究了直角凸壁面附近非对称位置空泡的动力学行为。具体分析了空泡的轮廓变形,形心的移动距离和方向,以及空泡射流的方向随着空泡与壁面相对位置d、h的变化规律。本文主要结论如下:(1)空泡的变形与空泡和固体壁面的相对位置d、h有关。随着空泡与右壁面的距离d的增大,空泡的非对称性越来越弱。随着空泡与上壁面的距离h的增大,在整个空泡的动力学过程中空泡的非球形特征逐渐减弱。(2)在空泡的溃灭和再生长过程中,空泡形心会持续地向左下方移动,且形心向左移动的距离随着d和h的增大而明显减小。(3)当空泡与上壁面的距离h适当时,会产生明显的斜向左下方的射流现象,且射流方向角θ随着d的增大而增大。

Cavitation damage widely exists in nuclear power plants.In order to reveal the mechanism of the cavitation damage in depth,this paper studies the dynamic behavior of the cavitation bubble at the asymmetric position near a right-angled convex wall based on the high-speed photographic experimental system.The contour deformation of the bubble,the moving distance and direction of the bubble centroid,and the change rule of the bubble jet direction with the relative position d and h of the bubble and the wall are analyzed in detail.The main conclusions of this paper are as follows:(1)The deformation of the bubble is related to the relative positions d and h.As the distance d between the bubble and the right wall increases,the asymmetry of the bubble becomes weaker.And as the distance h between the bubble and the upper wall increases,the non-spherical characteristics of the bubble gradually weaken during the entire dynamic process of the bubble.(2)During the collapse and regrowth of the bubble,the bubble centroid would continue to move to the lower left,and the moving distance of the bubble centroid decreases significantly with the increase of d and h.(3)When the distance h between the bubble and the upper wall is appropriate,there would be an obvious jet phenomenon towards the lower left,and the jet direction angle increases with the increase of d.