• CN:11-2187/TH
  • ISSN:0577-6686

›› 2012, Vol. 48 ›› Issue (16): 152-157.

• 论文 • 上一篇    下一篇

错位六弯叶桨搅拌假塑性流体的洞穴变化

栾德玉;周慎杰;陈颂英   

  1. 青岛科技大学机电工程学院;山东大学机械工程学院
  • 发布日期:2012-08-20

Cavern Development of Pseudoplastic Fluids Stirred by Impeller of Perturbed Six-bent-bladed Turbine

LUAN Deyu;ZHOU Shenjie;CHEN Songying   

  1. School of Mechanical and Electrical Engineering, Qingdao University of Science and Technology School of Mechanical Engineering, Shandong University
  • Published:2012-08-20

摘要: 预测洞穴大小及其变化规律对于剪切变稀的假塑性流体搅拌至关重要。利用计算流体力学(Computational fluid dynamics, CFD)模拟方法,对错位六弯叶桨搅拌黄原胶水溶液所形成的洞穴效应进行研究,确定较为适宜的洞穴边界速度,得到洞穴形状、直径及高径比随表观雷诺数 Re 的变化情况,并进行搅拌功率的试验验证。结果表明,模拟计算得到的功率值与试验测量值吻合较好,表明建立的层流模型正确;洞穴形状呈现圆柱形的变化规律,符合圆柱形洞穴模型(EN模型)的描述;Dc/D- NpRey 的变化规律和洞穴高径比的变化均与流体流变性无关,当Dc

关键词: 表观黏度, 错位六弯叶搅拌器, 洞穴, 假塑性流体

Abstract: The prediction of the cavern size is important in the mixing of shear-thinning fluids with yield stress. The cavern development of xanthan gum solutions, a pseudoplastic fluid with yield stress, stirred by a impeller of perturbed six-bent-bladed turbine was numerical researched using computational fluid dynamics(CFD). The cavern boundary velocity is properly determined and the cavern dimensions of shape, diameter and height to diameter ratio are obtained versus apparent Reynolds number, Re. In order to determine the capability of CFD to forecast the flow process, the agitational experiment is used to measure the power consumption. The results show that the power data predicted by the simulation are in good agreement with those measured in the experiment, which validate CFD model developed in laminar flow. The cylindrical cavern development is found as Re increased, which shows a good agreement with the representation of the cylindrical model (Elson’s model). The variations of dimensionless cavern diameter (Dc/D) verse dimensionless NpRey, as well as cavern height to diameter ratio, have nothing to do with the rheological index of fluids all together. CFD simulation predicts a linear slope of 0.35 from a log-log plot of Dc/D verse NpRey at Dc

Key words: Apparent viscosity, Cavern, Impeller of perturbed six-bent-bladed turbine, Pseudoplastic fluids

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