禹东峰, 刘建华, 穆科宇, 等. 高聚物管道流超大尺度结构特征实验研究[J]. 实验流体力学, 2024, 38(2): 1-8. DOI: 10.11729/syltlx20230105
引用本文: 禹东峰, 刘建华, 穆科宇, 等. 高聚物管道流超大尺度结构特征实验研究[J]. 实验流体力学, 2024, 38(2): 1-8. DOI: 10.11729/syltlx20230105
YU D F, LIU J H, MU K Y, et al. Experimental study of the characteristics of very-large-scale motions in polymer pipe flows[J]. Journal of Experiments in Fluid Mechanics, 2024, 38(2): 1-8. DOI: 10.11729/syltlx20230105
Citation: YU D F, LIU J H, MU K Y, et al. Experimental study of the characteristics of very-large-scale motions in polymer pipe flows[J]. Journal of Experiments in Fluid Mechanics, 2024, 38(2): 1-8. DOI: 10.11729/syltlx20230105

高聚物管道流超大尺度结构特征实验研究

Experimental study of the characteristics of very-large-scale motions in polymer pipe flows

  • 摘要: 高聚物减阻在管道输送中发挥着重要作用。管道湍流中的相干结构与高聚物减阻机理密切相关。实际工程中的管道流动大多为高雷诺数流动,高雷诺数管道流中最主要的含能相干结构为10倍管径量级的超大尺度结构。本文对高雷诺数高聚物管道流中的超大尺度结构进行实验研究。开展了4种高聚物浓度(以质量分数表征)、3种雷诺数共12组TR-PIV(Time-Resolved Particle Image Velocimetry)实验,使用预乘谱对超大尺度结构的尺度和强度特征进行了分析。研究结果表明,在相同雷诺数下,随着高聚物浓度增大,中心流区超大尺度结构的尺度和强度均明显增大,且与大尺度结构的强度之比也显著增大。在较高浓度下,超大尺度结构取代大尺度结构,成为了外区的主导含能结构。

     

    Abstract: Polymer drag reduction plays an important role in pipeline transportation. The drag reduction mechanism of polymer solutions is directly related to the coherent structure in pipe flows. High Reynolds number flows are the mainstream in the actual engineering, and very-large-scale structures with the streamwise length scale of 10 times pipe diameter are the most significant coherent structures in high Reynolds number pipe flows. In the present paper, experimental study is carried out on the very-large-scale structures in high Reynolds number polymer pipe flows. Premultiplied spectral analysis is used to examine the scale and strength properties of the very-large-scale structures in 12 sets of TR-PIV experiments with 4 polymer concentrations and 3 Reynolds numbers. The findings demonstrate that the scale and intensity of the very-large-scale structures in the central flow region significantly increase with an increase in the polymer concentration under the same Reynolds number, and the ratio of the intensity of the very-large-scale structures to that of the large-scale structures also significantly increases. The large-scale structure is replaced by the very-large-scale structure, which thereafter dominates as the main energy-containing structures in the outer region at elevated concentrations.

     

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