基于全流场的泵装置出水流道内流特性分析

Internal flow characteristic analysis on outlet conduit based on whole flow field

为了研究立式轴流泵装置出水流道的流动特性,以一立式轴流泵装置为研究对象,基于全流场非定常计算,结合湍动能和流线分布以及压力分布,分析出水流道内非定常流动特性;基于Q准则,在小流量工况下对流道内涡旋结构进行可视化分析;基于特征值法和涡量法,对不同工况下1个非定常旋转周期内的出水流道里的涡核进行提取.结果表明:小流量工况下,出水流道的入口处产生的涡旋结构数量最多,流道内提取到的涡核数量也最多;出水流道内的涡核强度从流道入口处往后逐渐减弱; 2种方法均在额定工况下提取到的涡核数量最少,并且额定工况下流道中后部均未出现涡核.掌握出水流道内流特性及涡核分布,有助于今后优化设计出低水力损失的出水流道.

In order to investigate the flow characteristics of the outlet conduit flow characteristics of the vertical axial-flow pump device,a certain pumping station was taken as the research object,and the numerical simulation was conducted on the model pump device based on the whole flow field.Combining with the turbulent kinetic energy,streamline distribution and pressure distribution,the dynamic characteristics of unsteady flow inside the outlet conduit were researched.Then,the Q criterion was used to analyze the vortex structure in the outlet conduit.Based on the eigenvalue method and the vorticity method,the vortex core was extracted from the outlet conduit under different working conditions in an unsteady rotation cycle.The results show that under part-load conditions,more vortex structures and vortex cores could be captured at the inlet of outlet conduit,and these vortex gradually disappear along the exit direction.Besides,the strength of vortex core reduces gradually as the fluid flows from the entrance of the outlet conduit.The number of vortex under the designed condition is the least for the two methods.Under the designed condition,there is no vortex core at the middle part.