同轴旋转圆台环隙流动机制及实验研究

Mechanism and experimental research on fluid flow in annulus of coaxial rotating conical cylinders

同轴旋转圆台环隙内流体的流动是基于经典的两同轴旋转圆柱环隙内泰勒库特流的一种扩展研究。通过流动显示实验和PIV粒子图像测速技术对圆台环隙的内部流场进行可视化和定量化的研究,分析涡运动的周期性规律,探究圆台环隙内雷诺应力分布和水位高度对流场的影响。研究表明,随着时间的发展,涡列周期性明显且整体在下移,当脉冲数为100脉冲/s时,环隙内形成均匀分布的正反交替的涡;当脉冲数为200~500脉冲/s时,存在快慢交替的分裂周期;在3种水位高度下也都存在明显周期性分裂,只是周期时间和涡的个数不同;平均流场存在上凸型外向流和下凹型内向流2种流态,流态的差异是离心力与静压力双重作用的强弱变化所致;雷诺应力分布中,径向正应力占主导,并主要集中在环隙中部。

The research on the flow fluid in the annulus of coaxial rotating conical cylinders originates from the classical Taylor Couette flow in the annulus of two coaxial rotating conical cylinders. This paper uses flow visualization experiments and PIV to display and quantify the internal flow field in the annulus of conical cylinders,and the periodic trends of vortex motions are studied to explore the effect of in-annulus Reynolds stress distribution and water level on the flow field. The study indicates that the periodic trends of vortex column move downward over time,and a series of alternate clockwise and anticlockwise vortices are uniformly distributed inside the annulus where pulse number is 100 pulse/s. There exists the alternating vortex fracture periods where pulse number is between 200-500 pulse/s. Under three different water levels,there exists obvious periodic fracture,but the periodic time and number of vortices are different. There are two types of flow（up-convex outward flow and down-concave inward flow） in the mean flow field,and the type of flow is decided by centrifugal force and static pressure. Radial normal stress dominates in Reynolds stress distribution and mainly exists in the middle of the annulus.