Abstract Helically coiled tubes are widely used in industry to enhance heat and mass transfer in the laminar flow regime, due to their secondary flow pattern. In this study, tomographic particle image velocimetry (tomo-PIV) is used in a horizontally coiled helical tube to systematically acquire 3C-3D velocity fields for Reynolds numbers ranging from 20 to 1400 and Dean numbers from 8 to 567. The velocity field evaluations are performed using two different approaches: time-averaged velocity field calculation from instantaneous velocity fields and velocity field determination by cross-correlation from an ensemble of instantaneous reconstructed volumes. Equivalent velocity field accuracy is achieved in both velocity approaches when the flow can be considered stationary. Moreover, numerical simulations were carried out in the same geometry at the same flow conditions and were validated against the experimental 3C-3D data sets. The simulation results show good agreement with the measured velocities, offering the possibility of parametric studies and design optimization. To the authors’ best knowledge, this is the first systematic experimental investigation of a helical coil flow by means of 3C-3D velocity measurements, which results can now be used for validation of numerical models in computational fluid dynamics. Graphic abstract Measured time-averaged velocity visualized by vector-magnitude colour at horizontal and vertical slices (left) and Dean vortices detected by 3D Q-criterion (right) from the time-averaged measurements (purple isosurfaces) and from the simulation (red isosurfaces) inside the helically-coiled tube at Re = 220 and De = 89.

中文翻译：

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水平定位螺旋盘管内二次流的层析 PIV 测量和 RANS 模拟

摘要 螺旋盘管由于其二次流型而广泛用于工业中以增强层流状态中的传热和传质。在这项研究中，断层扫描粒子图像测速 (tomo-PIV) 被用于水平盘绕的螺旋管，以系统地获取雷诺数范围从 20 到 1400 和迪恩数从 8 到 567 的 3C-3D 速度场。速度场评估是使用两种不同的方法执行：来自瞬时速度场的时间平均速度场计算和通过来自瞬时重建体积集合的互相关确定的速度场。当流动可以被认为是静止的时，两种速度方法都实现了等效的速度场精度。而且，数值模拟是在相同的几何形状和相同的流动条件下进行的，并针对实验 3C-3D 数据集进行了验证。模拟结果显示与测得的速度非常吻合，为参数研究和设计优化提供了可能性。据作者所知，这是首次通过 3C-3D 速度测量对螺旋线圈流进行系统实验研究，其结果现在可用于验证计算流体动力学中的数值模型。