微观表面形貌对螺旋槽液膜密封空化发生的影响

为探索微观表面形貌对液膜密封空化的影响,基于满足质量守恒的JFO空化模型及坐标变换,建立考虑微观表面形貌的双坝区螺旋槽液膜密封数学模型;采用有限体积法离散求解控制方程,综合分析表面粗糙度、周向波度和径向锥度对螺旋槽液膜密封空化发生的影响规律。结果表明:相比而言,密封面计入微观表面形貌后,摩擦副液膜中空穴区发生位置分散且形状不规则;以空化面积比为判据,较大表面粗糙度对液膜空化促生虽起到积极作用,但数据较小,可忽略不计;锥度对液膜中空穴促生和抑制影响有限,波幅的增加显著促进液膜中空穴的发生;高频波数时,正锥度有利于降低液膜空化面积比,抑制空穴。

Effects of Micro-surface Topography on Cavitation Occurrence of Spiral Groove Liquid Film Seals

In order to explore the effects of micro surface on the cavitation occurrence in the liquid film seals,based on the JFO cavitation model and coordinate transformation,the mathematical model of spiral groove liquid film seals with double dams considering the surface topography was established,and the governing equation was discretized by finite volume method.The effects of surface roughness,circumferential waviness and radial taper on the cavitation occurrence of spiral groove liquid film seals were analyzed.Results indicate that,by comparison,the locations of cavitation area in the liquid film are dispersed and the cavitation shapes are irregular after considering the micro-surface topography.By the cavitation area rate as the criterion,the lager surface roughness has a positive role in promoting cavitation occurrence,but the effects can be ignored because of the small data.The effects of radial taper on the induction and inhibition of cavitation are limited,while the increase of waviness amplitude prominently promotes the cavitation occurrence.At higher frequency waviness number,positive taper is helpful to reduce the ratio of liquid membrane cavitation area and inhibit cavitation.