Abstract The cavitation erosion characteristics of self-excited cavitating waterjet produced by a nozzle with various lip geometries were investigated. The cavitation erosive intensity was estimated by the mass loss of pure aluminum specimens and the sound press level of under the optimum standoff distance. The power spectrum density of noise and the surface profiles of the specimens were studied to uncover the influencing mechanism. The variables of lip geometries include: straight length ( L 1 / d = 0.15–0.75), expansion angles (0–40°), expansion length ( L 2 / d = 0.5–3). It is shown that the nozzle lip geometry can produce a significant influence on the cavitation erosion characteristics. The cavitation erosive ability can be affected by the straight length based on the vena contracta and pressure fluctuation feedback. The expansion structure can influence the jet’s cavitation erosive characteristic from two different aspects: the jet’s structuring frequency and the periodic behavior of the cavitation cloud. Moreover, it is possible to define an optimal geometry under this condition where the erosion mass loss is at a relative maximum, that is straight length L 1 / d around 0.35, expansion angle 10 ° θ 25 ° , length 1.0 L 2 / d 2.5 .

中文翻译：

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喷嘴唇几何形状对自激空化水射流空化冲蚀特性的影响

摘要 研究了不同唇形喷嘴产生的自激空化水射流的空化侵蚀特性。空化侵蚀强度通过纯铝试样的质量损失和最佳间隔距离下的声压级来估计。研究了噪声的功率谱密度和样品的表面轮廓，以揭示其影响机制。唇部几何形状的变量包括：直线长度（L 1 / d = 0.15-0.75）、膨胀角（0-40°）、膨胀长度（L 2 / d = 0.5-3）。结果表明，喷嘴唇的几何形状可以对气蚀特性产生显着影响。基于静脉收缩和压力波动反馈的直线长度可以影响空化侵蚀能力。膨胀结构可以从两个不同方面影响射流的空化侵蚀特性：射流的结构频率和空化云的周期行为。此外，可以在侵蚀质量损失相对最大的条件下定义最佳几何形状，即直线长度 L 1 / d 约为 0.35，扩展角 10 ° θ 25 ° ，长度 1.0 L 2 / d 2.5 .