射流压力对淹没水射流冲击与空蚀效果的影响

发布时间：2019-02-20 20:09

【摘要】：目的探究淹没水射流对铝合金及铜合金材料的冲击与空蚀作用。方法为获得关键射流工况参数对射流冲击和冲蚀效果的影响,对射流压力、冲击时间和靶距的作用进行了研究。在较低压力条件下对材料表面的残余应力进行测量与分析;在较高压力时对材料表面的破坏形貌进行观测。结果残余应力随射流压力的增加而增加,当冲击时间为20 min,射流压力为40 MPa时,残余应力达到最大值91 MPa;在空蚀作用初期,试样表面出现尺寸较小、呈离散分布的空蚀坑,其为离散空泡冲蚀所致。随着空蚀作用的增强,材料表面的空蚀坑增大,同时出现塑性变形,当冲击压力为300 MPa,靶距为7cm,冲击时间为15 min时,达到最显著冲击效果。结论当压力较小时,淹没水射流可以强化金属表面;当压力较大时,淹没水射流可以使金属表面产生空蚀坑和塑性变形。尽管淹没水射流具有连续的射流速度分布,但材料表面的破坏更多地取决于空化现象。
[Abstract]:Objective to investigate the impact and cavitation erosion of submerged water jet on aluminum alloy and copper alloy. Methods the effects of jet pressure, impact time and target distance on jet impingement and erosion were studied in order to obtain the effect of key jet operating conditions on jet impingement and erosion effect. The residual stress on the surface of the material was measured and analyzed under lower pressure, and the failure morphology of the surface was observed at higher pressure. Results the residual stress increased with the increase of jet pressure. When the impact time was 20 min, and the jet pressure was 40 MPa, the residual stress reached the maximum value of 91 MPa;. At the initial stage of cavitation erosion, small size cavitation pits with discrete distribution appeared on the surface of the specimens, which were caused by discrete cavitation erosion. With the increase of cavitation, the cavitation pit on the surface of the material increases and plastic deformation occurs. When the impact pressure is 300 MPa, target distance is 7 cm, the impact time is 15 min, the most significant impact effect is achieved. Conclusion when the pressure is small, the submerged water jet can strengthen the metal surface, and when the pressure is high, the submerged water jet can cause cavitation pit and plastic deformation on the metal surface. Although the submerged water jet has a continuous velocity distribution, the destruction of the material surface depends more on the cavitation phenomenon.
【作者单位】：江苏大学材料科学与工程学院;江苏大学能源与动力工程学院;
【基金】：国家自然科学基金(51205171,51376081)~~
【分类号】：TG178

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