涡轮桨搅拌槽内湍流特性的V3V实验及大涡模拟

doi:10.11949/j.issn.0438-1157.20170594

摘要/Abstract

摘要：

分别用体三维速度测量技术（volumetric three-component velocimetry measurements，V3V）和大涡模拟（large eddy simulation，LES）方法对涡轮桨搅拌槽内流场进行研究，发现在完全湍流状态下，涡轮桨搅拌槽内流场的量纲1相平均速度及湍动能分布同Reynolds数无关。用V3V方法实现了Rushton桨叶附近三维流场的重构；探讨尾涡的三维结构及运动规律；分析了叶片后方30°截面轴向、径向和环向速度沿径向分布规律。用V3V实验结果对比了2D-PIV（particle image velocimetry）数据中的尾涡涡对位置和涡量，涡对位置吻合度较好，但2D-PIV中涡量较V3V小37.5%；通过大涡模拟得到完整的尾涡结构，发现在叶片上边缘后侧存在一个和尾涡形成方式相同但不成对出现的涡结构；将大涡模拟结果和2D-PIV及V3V实验结果对比发现，大涡模拟在速度分布及尾涡运动轨迹方面均同实验结果吻合较好，表明大涡模拟能较好地预测涡轮桨搅拌槽内流场。

关键词: V3V, PIV, 大涡模拟, 尾涡, 涡轮桨

Abstract:

The volumetric three-component velocimetry (V3V) measurements and the large eddy simulation (LES) were used to study the flow field near the standard Rushton impeller in a stirred vessel. The results of V3V indicate that the Reynolds number has almost no influence on the normalized phase-resolved velocity and TKE when the flow field is absolutely turbulent. The structure and movement law of trailing vortices are discussed by reconstruction of the three-dimensional flow field with V3V. The distributions of radial, axial and tangential velocities in 30℃ross-section behind the impeller were analyzed. The distributions of vortex pair by V3V were in good agreement with these by 2D-PIV (particle image velocimetry), however the vorticity by V3V is about 37.5% larger. LES method was used to simulate flow field in stirred tank with Rushton turbine impeller. The velocity distribution and trailing trajectory of LES results are in good agreement with the 2D-PIV and V3V data. Complete structure of the trailing vortices had been obtained and a vortex, which is similar with trailing vortices, was discovered near the up surface of the impeller.

Key words: V3V, PIV, LES, trailing vortex, Rushton impeller

中图分类号:

TQ022

施乃进, 周勇军, 鲍苏洋, 辛伟, 陶兰兰. 涡轮桨搅拌槽内湍流特性的V3V实验及大涡模拟[J]. 化工学报, 2017, 68(11): 4069-4078.

SHI Naijin, ZHOU Yongjun, BAO Suyang, XIN Wei, TAO Lanlan. V3V study and large eddy simulation of turbulence characteristics in a stirred vessel with Rushton turbine impeller[J]. CIESC Journal, 2017, 68(11): 4069-4078.

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