YSC178A型液动锤射流元件底盖板外壁冲蚀机理

Erosion Mechanism on Outer Wall of Bottom Plate of Fluidic Element for YSC178A Liquid-Jet Hammer

应用CFD动态分析技术,对具有内分流结构的YSC178A型液动锤的速度场进行了研究,分析了不同形状不同尺寸的分流孔对速度场的影响。研究发现:在一定直径的圆柱形分流孔出口处附近存在分流流束附壁现象,且附壁的分流流束特征与冲蚀坑的形状和大小之间有较好的对应关系,表明YSC178A型液动锤射流元件底盖板外壁出现冲蚀坑是由从一定直径的圆柱形分流孔喷出的分流流束附壁冲蚀造成的;分析结果还显示,喇叭形分流孔大大优于圆柱形分流孔,足够长且出口直径较大的喇叭形分流孔,其出口处附近流束附壁现象大幅度减轻以致消失,可以大幅度降低高速射流能量并减弱分流流束对底盖板外壁的冲蚀,避免出现显著冲蚀坑。

The flow velocity fields of YSC178A liquid-jet hammer with internal flow-dividing mechanism was investigated by means of CFD dynamic analysis.The influence of the flow-dividing holes in different shapes and sizes was analyzed.It is found that there exists the phenomenon of flow-dividing jet attached to the wall near the exit of cylindrical hole in a certain diameter.And there was a relatively good one-to-one correspondence relationship between the character of flow-dividing jet and the shapes as well as sizes of the erosion pits.This indicates that the eroded pits were caused by jet attachment as the liquid flowed out from flow-dividing hole in a great diameter,and the horn-like holes are superior to cylindrical flow-dividing holes.When the flow-diving dole is long enough and its diameter is very large,the degree of jet attachment at the exit of the proper horn-like hole decreases sharply,and even disappears,which reduces sharply the energy of high-speed jet and weakenes the erosion in the outer walls of the bottom and top plates of the fluidic element to avoid significant erosion pits.