Research On The Effects Of Solid Particles In Laser-induced Bubble And Cavitation

Cavitation erosion is a common cause of damage in hydraulic machinery.The study of cavitation has aroused widespread concern.Laser induced cavitation has become the core of the research technology of cavitation.Compared with the traditional research methods,it has the characteristics of strong controllability,simple operation and high accuracy.It can be used in many fields,such as hydraulic machinery,biomedicine,electronic information and so on.In reality,solid particles are an important factor affecting cavitation.The study of the mechanism of solid particles on laser induced cavitation can help to further uncover the cavitation mechanism and effectively solve the damage of cavitation,which is of great significance to the field of hydraulic machinery.In this paper,nanosecond laser is used as excitation source to study the effect of solid particles on laser-induced cavitation characteristics and cavitation effect.With the help of high speed camera technology,the transient characteristics of laser induced cavitation are detected.The effect of laser energy on the bubble pulsation in solid-liquid two phase flow is studied.The effect of solid particles on laser induced cavitation is studied.The effect of laser induced cavitation on the surface morphology of the target is found.The specific research contents are as follows:(1)Based on the cavitation and bubble dynamics theory,the mechanism of cavitation by liquid medium and solid particles was studied.The influence of solid particles on laser-induced cavitation was researched in combination with the mechanism of laser breakdown of liquid medium,which provided theoretical support for subsequent experiments.(2)The effect of solid particles on laser-induced cavitation was experimentally studied,and the influence of laser energy on the transient characteristics of laser cavitation was tested.It is found that the cavitation motion is closely related to the laser energy.The effects of solid particles on laser induced cavitation were analyzed and compared.The effects of solid particles on laser induced cavitation were further investigated.The pulsation process of near wall cavitation in solid-liquid two phase flow was studied,and the phenomena of high velocity jet,shock wave and wall movement of vacuoles were found.(3)The effect of laser induced cavitation on the surface morphology of target was experimentally studied.The effects of defocus,laser energy and solid particles on the surface morphology of the target were studied with the help of 3D topography detection and surface micromorphology detection,and the effect of laser induced cavitation was analyzed.It was found that solid particles can promote the effect of laser induced cavitation.