Maurin Artur
Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Hydropower Department, Fiszera 14 St., 80-231 Gdańsk, Poland.
Materials (Basel). 2021 Jun 7;14(11):3131. doi: 10.3390/ma14113131.
The degradation process of 316L stainless steel caused by cavitation was investigated by means of finite element analysis. The damage characteristics of metal specimens subjected to the cavitation bubble collapse process were recreated by simulation with a micro-jet water hammer. The simulation results were compared with the cavitation pits created in the experimental tests. In the experiment, different inlet and outlet pressures in a test chamber with a system of barricade exciters differentiated the erosion process results. Hydrodynamic cavitation caused uneven distribution of the erosion over the specimens' surface, which has been validated by roughness measurements, enabling localisation and identification of the shape and topography of the impact pits. The erosion rate of the steel specimens was high at the beginning of the test and decreased over time, indicating the phase transformation and/or the strain-hardening of the surface layer. A numerical simulation showed that the impact of the water micro-jet with a velocity of 100 m/s exceeds the tensile strength of 316L steel, and produces an impact pit. The subsequent micro-jet impact on the same zone deepens the pit depth only to a certain extent due to elastoplastic surface hardening. The correlation between post-impact pit geometry and impact velocity was investigated.
通过有限元分析研究了空化作用下316L不锈钢的降解过程。利用微射流水锤模拟再现了金属试样在空化气泡溃灭过程中的损伤特性。将模拟结果与实验测试中形成的空蚀坑进行了比较。在实验中，带有障碍物激励器系统的试验腔内不同的进出口压力使侵蚀过程结果有所不同。水力空化导致试样表面侵蚀分布不均，这已通过粗糙度测量得到验证，从而能够定位和识别冲击坑的形状和形貌。钢试样的侵蚀速率在试验开始时较高，随时间降低，表明表面层发生了相变和/或应变硬化。数值模拟表明，速度为100 m/s的水微射流的冲击超过了316L钢抗拉强度，并产生了一个冲击坑。由于弹塑性表面硬化，随后在同一区域的微射流冲击仅在一定程度上加深了坑深。研究了冲击后坑的几何形状与冲击速度之间的相关性。
