1. Department of Mechanical Engineering, Jiangsu University, Zhenjiang,Jiangsu 212013, China; 2.National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China
Abstract:Cavitation corrosion of hydraulic machinery is complicated. Surface corrosion resistance technology is hard to achieve. A well controllable nanosecond pulsed laser was used to induce cavitation. The feature images of plasma cavity, cavitation shock wave and bubble pulsation were acquired by a highspeed camera. The influence of laser parameters on the cavitation characteristics such as bubble size and fluctuation time was analyzed. Combined with acoustic signals collected by hydrophone. The pressure of shock wave was analyzed. The residual stress in the laser action region was measured to characterize the surface properties of the material. The relationship between laser parameters and surface properties was analyzed. The experimental results show that the semicircular plasma cavity is generated by the optical breakdown effect. The larger the laser energy is, the longer the period of cavitation bubble pulsation is, and the larger the size of the cavitation bubble is. Shock wave images are clearly acquired when the laser bubble rebounds. The shock wave pressure is almost linearly related to the laser energy. The residual compressive stress is close to the original value under the small energy laser. Under the influence of large energy laser, the residual compressive stress increases rapidly. Residual compressive stress is almost linearly related to the laser energy, and the force is stable. These results provide a reference for research on the cavitation erosion mechanism and control countermeasures.
[1]FRIEDRICHS J, KOSYNA G. Rotating cavitation in a centrifugal pump impeller of low specific speed[J]. Journal of fluids engineering, 2002, 124(2):356-362.
[2]THAI Q, LEE C. The cavitation behavior with short length blades in centrifugal pump[J]. Journal of mechanical science & technology, 2010, 24(10):2007-2016.
[3]WOLOSZYNSKI T, PODSIADLO P, STACHOWIAK G W. Efficient solution to the cavitation problem in hydrodynamic lubrication[J]. Tribology letters, 2015, 58(1):1-11.
[4]龙新平, 程茜, 韩宁,等. 射流泵空化流动的数值模拟[J]. 排灌机械工程学报, 2010, 28(1):7-11.
LONG Xinping,CHENG Qian,HAN Ning,et al. Numerical simulation on cavitation flow with jet pump[J]. Journal of drainage & irrigation machinery engineering, 2010, 28(1):7-11.(in Chinese)
[5]吕涛, 陈昉, 张伟. 聚焦调Q脉冲激光水下诱导空化泡和冲击波实验研究[J]. 激光与光电子学进展, 2015, 52(5):129-136.
LYU Tao,CHEN Fang,ZHANG Wei. Experimental study of cavitation bubble and shock wave induced by Qswitched focused laser pulse underwater[J]. Laser & optoelectronics progress, 2015, 52(5):129-136. (in Chinese)
[6]YANG Y X, WANG Q X, KEAT T S. Dynamic features of a laserinduced cavitation bubble near a solid boundary[J]. Ultrasonics sonochemistry, 2013, 20(4):1098-103.
[7]ORTHABER U, PETKOVEK R, SCHILLE J, et al. Effect of laserinduced cavitation bubble on a thielastic membrane[J].Optics & laser technology, 2014, 64(64):94-100.
[8]REN X D, HE H, TONG Y Q, et al. Experimental investigation on dynamic characteristics and strengthening mechanism of laserinduced cavitation bubbles[J]. Ultrasonics sonochemistry, 2016, 32:218-223.
[9]KOCH M, LECHNER C, REUTER F, et al. Numerical modeling of laser generated cavitation bubbles with the finite volume and volume of fluid method using OpenFOAM[J]. Computers & fluids, 2016, 126(3):71-90.
[10]CHEN T N, GUO Z N, ZENG B W, et al. Experimental research and numerical simulation of the punch forming of aluminum foil based on a laserinduced cavitation bubble[J]. International journal of advanced manufacturing technology, 2017(1):1-10.
[11]陈笑. 高功率激光与水下物质相互作用过程与机理研究[D]. 南京:南京理工大学, 2004.
[12]鲁建英, 耿德珅, 陈朗. 强激光水中诱导等离子体冲击波数值模拟[J]. 中国激光, 2015, 42(9):14-21.
LU Jianying,GENG Deshen, CHEN Lang.Numerical simulation of high intensity of laser induced plasma shock wave in water[J]. Chinese journal of lasers, 2015, 42(9):14-21. (in Chinese)
[13]左成亚. 2A02铝合金激光诱导空泡力学效应及其强化机理的研究[D].镇江:江苏大学,2016.
[14]刘志东,杨怡生.脉冲激光强化材料中冲击波的压强及其传播估算[J].航空制造技术,1993(3):19-22.
LIU Zhidong, YANG Yisheng. Shockwave pressure and propagation estimation in pulsed laser enhanced materials[J]. Aeronautical manufacturing technology, 1993(3):19-22. (in Chinese)