Experimental and numerical visualizations of swirling flow in a vertical pipe
Experimental and numerical visualizations of swirling flow in a vertical pipe
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DOI：
10.1007/s12650-015-0340-8
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发表时间：
2016-08
影响因子：
1.7
通讯作者：
A. Hamdani;T. Ihara;H. Kikura
中科院分区：
文献类型：
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作者：
A. Hamdani;T. Ihara;H. Kikura
本文对垂直管道内扭带诱导的湍流旋转流动进行了实验和数值模拟的比较。发展了一种新的测量技术-相控阵超声速剖面仪（UVP），用于旋转流场的二维可视化。设计了一种基频为4 MHz的相控阵，它有8个压电元件，每个元件发射超声束。这种传感器的优点是可以通过改变每个元件的信号传输的时间延迟来容易地控制超声波束。提出了一种矢量重建算法，显示了如何从两个接收器元件的输出信号中提取的多普勒频移计算粒子的速度矢量。二维速度场已被可视化，它被发现，正如预期的那样，旋流的存在导致显着增加的幅度测得的切向速度。此外，进行了数值计算，并与实验结果进行了定性比较。数值计算结果通过使用商业CFD代码FLUENT®v.14.5和RNG k-ε湍流模型求解三维、雷诺平均Navier-Stokes方程获得。相控阵UVP和CFD计算结果的定性比较表明，与平均速度场吻合较好。总结并讨论了基于旋流效应的实验和数值结果以及参数趋势。图形摘要
AbstractThis paper presents a comparison between the experimental and numerical simulations of turbulent swirling flow induced by twisted tape in vertical pipe. A novel measurement technique, phased array ultrasonic velocity profiler (UVP), has been developed for 2D velocity field visualization in swirling flow. A phased array with basic frequency 4 MHz has been designed, it has eight piezoelectric elements and each element transmits ultrasound beam. The advantage of this sensor is that the ultrasound beam can be controlled easily by changing the time delay of signal transmission for each element. A vector reconstruction algorithm is presented showing how the velocity vector of particles can be calculated from Doppler-shift frequencies taken from the output signals of two receiver elements. Two-dimensional velocity field has been visualized and it is found, as expected, that the presence of swirl cause a significant increase in the magnitude of the measured tangential velocity. Furthermore, a numerical calculation is performed and qualitatively compared with experimental results. The numerical result is obtained by solving three-dimensional, Reynolds-averaged Navier–Stokes equations by the commercial CFD code FLUENT®v.14.5 with RNG k-ε turbulence model. The qualitative comparison between phased array UVP and CFD results shows good agreement with the average velocity field. Experimental and numerical findings and parametric trends based on the effects of swirling flow are summarized and discussed.Graphical abstract