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运用高速数码摄像系统对比转速为700的轴流泵在最优工况流量下不同空化程度时的叶顶间隙内空化流动进行拍摄实验,捕捉到空化发生位置和空泡团形态随空化程度变化的演变过程。实验结果表明:叶顶间隙内空化发生的初始位置位于叶顶翼型头部,空泡团为沿叶片工作面向背面旋转的旋涡空化,旋转轴和圆周方向基本一致;随着泵汽蚀余量的降低,空化发生位置和空泡团与叶顶翼型粘连的区域均呈由叶顶翼型头部向尾部延伸发展的趋势;当泵发生汽蚀时,空化发生位置覆盖整个叶顶翼型,间隙空泡团和叶片背面空泡团相掺混,对叶轮流道内液相主流产生强烈干扰,导致泵能量性能急剧下降。研究结果为轴流泵叶顶间隙内空化发生及发展过程的理论研究提供了有效参考。
Using high-speed digital camera system compared to the speed of 700 axial flow pump in the optimal conditions of flow rate of different cavitation when the cavitation flow within the blade roof to capture the experiment to capture the occurrence of cavitation and empty bubble group form with the empty The evolution of the degree of change. The experimental results show that the initial cavitation position in the tip clearance is located at the tip of the blade tip airfoil. The cavitation is a vortex cavitation that rotates along the working surface of the blade toward the back surface. The rotation axis and the circumferential direction are basically the same. The reduction of the residual volume, the occurrence of cavitation and the adhesion of cavities to the tip airfoil tend to extend from the tip to the tail of the tip airfoil. When the pump cavitates, the cavitation occurs in the whole area Leaf tip airfoil, interstitial cavitation group and voids on the back of the blade were mixed, causing strong interference with the main stream of liquid phase in the impeller runner, resulting in a sharp drop in pump energy performance. The results provide an effective reference for the theoretical research on the occurrence and development of cavitation in the tip clearance of axial flow pump.