To gush out syringe needle and nozzle surface export to, Attain the curves of pressure distribution with different degrees and water head, and predict the area of cavitation changing with the different degree and water head. 针对喷针头和喷管出口内表面,得到不同开度和水头下的压力分布曲线,预测空蚀区域随开度和水头变化的规律。