Laser-Doppler measurements of the turbulent flow in stirred vessels to establish scaling rules
Laser-Doppler measurements of the turbulent flow in stirred vessels to establish scaling rules
复制标题
激光多普勒测量搅拌容器中的湍流以建立缩放规则
DOI：
10.1016/0009-2509(78)85081-7
复制
发表时间：
1978
影响因子：
4.7
通讯作者：
H. V. Maanen
中科院分区：
文献类型：
--
作者：
K. V. D. Molen;H. V. Maanen
本文采用激光多普勒测速仪测量了直径为0.12、0.29和0.90 m的搅拌槽内的湍流流动。容器中装有水，并在叶轮流区进行测量。导出了平均速度、周期分量、湍流强度和湍流功率谱的标度规则。看来，接近叶轮的流动是由叶轮叶片后面的尾涡的周期性波动流动主导的。尾涡中的标准化平均速度以及因此靠近叶轮的湍流强度对叶轮几何形状非常敏感，并且随着容器的尺寸略微增加。在叶轮流区的大部分区域，功率谱在对数-对数尺度上有一个斜率为-5 2的截面，因此，小涡的能量随着尺度的增加而减小。在血管壁处，旋涡完全衰减为随机湍流，频谱显示为-5 3斜率。
A laser-Doppler velocimeter, equipped with a frequency shift so as to eliminate directional ambiguity, has been used to measure the turbulent flow in stirred vessels with diameters of 0.12, 0.29 and 0.90 m of the same geometry. The vessels contained water and measurements were done in the impeller stream region. Scaling rules have been derived for average velocity, the periodic component, turbulent intensities and turbulence power spectra. It appears that close to the impeller the flow is dominated by the periodically fluctuating flow of the trailing vortices behind the impeller blades. The normalized mean velocity in the trailing vortices, and therefore the turbulence intensity close to the impeller, is very sensitive to impeller geometry and shows a slight increase with size of the vessel. In the greater part of the impeller stream region the power spectra have a section with a− 5 2 slope on a log-log scale and consequently the energy of the small eddies decreases with increasing scale. At the vessel wall the vortices have decayed completely to random turbulence and the spectrum shows a− 5 3 slope.