高频脉动气体射流喷头仿真设计

为改善飞秒激光加工形貌及提高加工深度，设计一种高频脉动气体射流系统。利用双稳态射流开关实现高频振动与射流的耦合，形成脉动射流。该结构形成脉动射流主要存在2种机制：一是质量流进入空气产生的声压，在理论上能够产生大约2 500 Hz的振动；二是射流在开启和关闭过程产生的振动。运用CFD技术探究了射流喷头各项结构参数对射流效果的影响，仿真结果表明控制流道宽度、侧壁倾角、主流道宽度分别对切换时间、压力振幅、出口速度的影响最大，侧壁倾角为12°，控制流道宽度为0.7 mm且垂直于输出流道，劈距为8 mm，主流喷嘴宽度和主流道宽度为1 mm时得到最理想的优化结果。

Simulation Design of High Frequency Pulsating Gas Jet Nozzle

In order to improve the femtosecond laser processing morphology and increase the processing depth,a high-frequency pulsating gas jet system was designed.The bistable fluidic switch was used to realize the coupling of high frequency vibration and the jet to form a pulsating jet.There are two mechanisms for the structure to form a pulsating jet:the first is the sound pressure generated by the mass flow entering the air,which can theoretically generate vibrations of about 2 500 Hz;the second is the vibration generated by the jet during the opening and closing process.The CFD technology was used to explore the influence of various structural parameters of the jet nozzle on the jet effect.The simulation results show that the control runner width,the sidewall inclination and the power runner width have the greatest influence on the switching time,the pressure amplitude and the outlet velocity,respectively.When the sidewall inclination is 12°,the control runner width is 0.7 mm and it is perpendicular to the output runner,the splitter distance is 8 mm,and the power nozzle width and the power runner width are 1 mm,the most ideal optimization results are obtained.