Abstract Studying the decay characteristics and effective swirl length of the gas-liquid two-phase swirling flow generated by vortex tools is of great significance for improving its drainage effect. The effective swirl length is a key parameter related to the working performance, installation spacing and downstream pressure dynamics of vortex tools. However, works addressing the effective swirl length are rare in the literature. In this research, the decay characteristics and effective swirl length of a swirling flow and the factors that affect the swirling flow are systematically investigated using the orthogonal numerical simulation experiment method. Good agreements are achieved between existing experimental data and the numerical results of this study. The range analysis results reveal that the helix angle, mandrel diameter and vane axial length play dominant roles in the initial swirl intensity. An increase in the helix angle results in a decrease in the initial swirl intensity, while the mandrel diameter has the opposite effect. The swirl intensity decay rate is mainly affected by the Reynolds number, helix angle and vane axial length; the decay rate has a negative correlation with the first two factors and a positive correlation with the third factor. On this basis, a comprehensive decay model of the swirl intensity is proposed after obtaining the correlations for the geometrical swirl intensity and swirl intensity decay rate. Furthermore, an effective swirl length evaluation method is established, and the optimal vortex tool structure of a typical gas well is obtained with a helix angle of 55°, a mandrel diameter of 38 mm, a vane axial length of 120 mm and a vane width of 15 mm.

中文翻译：

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旋涡工具插入管内旋流衰减特性及有效旋流长度的正交数值模拟实验研究

摘要 研究涡流工具产生的气液两相涡流的衰减特性和有效涡流长度，对于提高其排水效果具有重要意义。有效涡流长度是与涡流工具的工作性能、安装间距和下游压力动态相关的关键参数。然而，解决有效涡流长度的工作在文献中很少见。本研究采用正交数值模拟实验方法，系统地研究了旋流的衰减特性、有效旋流长度以及影响旋流的因素。现有实验数据与本研究的数值结果之间取得了良好的一致性。极差分析结果表明，螺旋角，心轴直径和叶片轴向长度在初始涡流强度中起主导作用。螺旋角的增加导致初始涡流强度的降低，而心轴直径具有相反的效果。旋流强度衰减率主要受雷诺数、螺旋角和叶片轴长的影响；衰减率与前两个因素呈负相关，与第三个因素呈正相关。在此基础上，在获得几何涡流强度和涡流强度衰减率的相关关系后，提出了涡流强度的综合衰减模型。进一步建立了有效的旋流长度评价方法，得到了典型气井的最优涡旋工具结构，螺旋角为55°，心轴直径为38 mm，