Adaptability Analysis of Second Generation Vortex Recognition Method in Internal Flow Field of Mixed-flow Pumps

ZHAO Binjuan, XIE Yuntong, LIAO Wenyan, HAN Luyao, FU Yanxia, HUANG Zhongfu
2020 Journal of Mechanical Engineering  
摘要:流体机械内部涡的产生会严重影响流体机械的内流场及外性能,速度、压力等传统方式并不能全面揭示流场真实的流 动情况,而涡识别方法可以表征混流泵内部涡结构,识别涡的大小、位置和演变规律。采用大涡模拟对混流泵内部流场进行 高精度数值模拟,由此获得不同涡识别方法(涡量、螺旋度方法、λ 2 准则和 Q 准则)在混流泵内流场中识别出的涡结构。结果 表明:与涡量准则法相比,采用第二代涡识别方法更能获得详细的混流泵内部的涡结构。其中,Q 准则能剔除绝大部分的剪 切层影响,较其他涡识别方法更好地捕捉混流泵内部的涡结构,显示的涡大小更加精确。通过 Q 准则的识别,提取了混流泵 叶轮流道内规则的通道涡,此类型涡结构均匀分布在各个流道,叶片叶顶泄漏涡结构清晰,摆脱了壁面剪切层的干扰;导叶 叶片靠近轮毂处同样获取了规则的通道涡,通道涡均匀的分布在各个流道内,叶片尾缘脱落涡摆脱了壁面剪切层的干扰,可 以看到清晰的涡结构。Q 准则在第二代涡识别方法中脱颖而出,更适用于混流泵内流场的涡识别,在涡结构以及涡大小的显 示方面都具有优势,可用于旋转机械内流场的分析。 * 关键词:混流泵;大涡模拟;涡识别;Q
more » ... 度方法;λ 2 准则 Abstract:Internal and external properties of fluid machinery are affected by the vortices generated in the machine. Traditional methods such as speed and pressure fail to reveal the true flow of the flow field. The vortex identification method succeeds in characterizing the internal vortex structure of the mixed-flow pump and identifying the size and position of the vortex and evolution. Large eddy simulations are used to obtain the vortex structures of different vortex identification methods (vorticity, helicity method, λ 2 criterion, and Q criterion) in the flow field of a mixed-flow pump. The results show that the second generation vortex identification method can obtain the detailed vortex structure inside the mixed-flow pump more than the vorticity criterion method. Among them, the Q criterion eliminates most of the influence of the shear layer, and presents the obvious superiority in capturing the vortex structure inside the mixed flow pump, and accurately displaying the vortex size. Through the identification of the Q criterion, the regular channel vortices in the impeller flow channel of the mixed-flow pump are extracted and evenly distributed in each flow channel. The structure of the vortex leakage at the blade tip is clear, and the interference of the shear layer on the wall is eliminated. In order to form a regular channel vortex, the blade trailing edge vortex sheds the interference of the wall shear layer, and a clear vortex * 国家自然科学基金(51609107)、江苏省高校优势学科建设工程和西华大学 省部级学科平台开放课题(szjj2018-123)资助项目。20190910 收到初稿, 20200209 收到修改稿
doi:10.3901/jme.2020.14.216 fatcat:vvosz4xwtzcsppzdkrnzv24iqq