Direct determination of energy dissipation in stirred vessels with two-point LDA
Direct determination of energy dissipation in stirred vessels with two-point LDA
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DOI：
10.1002/aic.10468
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发表时间：
2005-08-01
期刊：
影响因子：
3.7
通讯作者：
Yianneskis, M
中科院分区：
文献类型：
--
作者：
Ducci, A;Yianneskis, M
采用多点LDA技术测定了拉什顿水轮机搅拌容器内的总体平均动能粘滞耗散率。在叶轮流中直接测量了构成耗散率的12个均方速度梯度中的9个，并研究了流动与局部各向同性的偏差。用(ND2)-D-3归一化的耗散率（其中N和D分别代表叶轮转速和叶轮直径）在雷诺数为20,000-40,000时近似为常数，而波动梯度随叶片角位置变化显著，变化幅度可达总体平均值的三倍。还通过局部湍流动能平衡评估了整体平均耗散率值。(c) 2005年美国化学工程师学会
The ensemble-averaged kinetic energy viscous dissipation rate was determined with a multipoint LDA technique in a vessel stirred by a Rushton turbine. Nine out of the total of 12 mean squared velocity gradients constituting the dissipation rate were directly measured in the impeller stream, and the deviation of the flow from local isotropy was investigated. The dissipation rate normalized with (ND2)-D-3, where N and D are the impeller rotational speed and the impeller diameter, respectively, was found to be approximately constant for Reynolds numbers of 20,000-40,000, whereas the fluctuating gradients were found to vary significantly, by up to three times the ensemble-averaged values, with blade angular position. The ensemble-averaged dissipation rate values were also assessed through a local turbulence kinetic energy balance. (c) 2005 American Institute of Chemical Engineers