环形激光诱导空化泡的数值仿真分析

Numerical Simulation of Ring-shape Laser-induced Cavitation Bubble

激光诱导前向转移技术是一种有效的物质传输手段,但在单细胞传送时,存在传送精度低等问题。提出将环形空化泡运用在激光诱导前向转移技术上,进而解决物质传送精度差的问题。利用有限元数值仿真分析方法,探究环形激光诱导环形空化泡的生长溃灭过程。并对其流场中不同方向的速度场进行了分析,发现了环形空化泡膨胀初期对环外部溶液的推动阻隔效应和溃灭后的能量中心汇聚效应均可运用在物质的精确转移技术中。基于响应曲面法,探究激光能量、环形光斑内外径比值、海藻酸钠溶液质量分数对环形空化泡水平和垂直方向最大速率的影响强弱顺序,得出各因素对最大速率的影响强弱顺序由大到小依次为:环形光斑内外径比值、海藻酸钠溶液质量分数、激光能量。其水平和垂直方向最大速率在环形光斑内外径比值为0.7(70μm/100μm)、激光能量60μJ、溶液质量分数为1%时达到最佳值,分别为14.28 m/s和11.82 m/s。

Laser induced forward transfer technology is an effective means of material transmission,but it has the problem of low transmission accuracy in single cell transmission.The purpose is to verify the feasibility of ring cavitation bubble in laser-induced forward transfer technology,and to solve the problem of poor single cell transmission accuracy.The growth and collapse process of annular cavitation bubble induced by ring laser were studied by using the finite element numerical simulation method.The velocity fields in different directions in the flow field were analyzed.It was found that the pushing and blocking effect of the annular cavitation bubble on the solution outside the ring at the initial stage of expansion and the energy center convergence effect after collapse can be used in the transmission technology that can improve the accuracy of single cell printing technology.Based on the response surface method,the order of the influence of laser energy,ratio of inner and outer diameter of annular spot and mass fraction of sodium alginate solution on the horizontal and vertical maximum velocity of annular cavitation bubble was investigated.The results show that the order of the influence of various factors on the maximum rate is as follows:the ratio of the inner and outer diameter of the annular spot,the mass fraction of sodium alginate solution,and the laser energy.When the ratio of inner diameter to outer diameter of the annular spot is 0.7(70μm/100μm),the laser energy is 60μJ,and the mass fraction of solution is 1%,the maximum horizontal and vertical velocities are 14.28 m/s and 11.82 m/s respectively.