基于纸浆泵流场数值模拟的叶轮设计准则及其应用

Impeller design criterion based on numerical simulation of stock pump flow field and its application

采用纤维-流动耦合模型及求解方法,对纸浆泵叶轮流道内的悬浮流动进行了数值模拟.结果表明,在进口附近,纤维取向变化剧烈,在靠近凹壁面附近,纤维取向摆动显著,而沿中间流线及凸壁面流线,纤维取向变化相对比较稳定;在进口靠近凹壁面附近,附加应力比较显著,而在流道中间及下游区域,附加应力分布变得平均.将结论推广至纸浆泵叶轮设计中,得出了4个设计准则,即叶片前1/3长度上的大曲率半径准则、流道扩张角准则、大包角准则和叶片出口角准则.以准则筛选法为基础,纳入上述4个准则,建立了纸浆泵叶轮的设计系统.通过系统设计了一台样机,经检测效率在原设计基础上提高了6%,比纸浆泵行业标准提高了3%.

The model of fiber-flow coupling and the solving procedures are presented.The method is applied to the numerical simulation of the fiber suspension through the stock pump impeller.The results show that,the fiber orientations change drastically in the vicinity of the inlet;near the concave wall region the orientations flip obviously;and along the mid-streamline and the streamline close to the convex wall,the orientations become more stable.The extra stress is significant along the concave wall close to the inlet,and it becomes uniform in the middle region and the downstream region.The results are further extended to the design of the stock pump impeller.Four design criterions are obtained as follows： the large radius of curvature on the first one third part of the blade,the channel expansion angle criterion,the large wrap angle criterion,and the blade outlet angle criterion.These criterions are added into the existing optimization system based on hydraulic design criterions.A stock pump impeller design system is developed.Then a new stock pump impeller is designed and the tested pump efficiency is 6% more than the original machine,and is 3% more than the Chinese stock pump standard.