The hydrodynamics of secondary flow phenomena in a disc‐shaped gas vortex unit (GVU) is investigated using experimentally validated numerical simulations. The simulation using ANSYS FLUENT^® v.14a reveals the development of a backflow region along the core of the central gas exhaust, and of a counterflow multivortex region in the bulk of the disc part of the unit. Under the tested conditions, the GVU flow is found to be highly spiraling in nature. Secondary flow phenomena develop as swirl becomes stronger. The backflow region develops first via the swirl‐decay mechanism in the exhaust line. Near‐wall jet formation in the boundary layers near the GVU end‐walls eventually results in flow reversal in the bulk of the unit. When the jets grow stronger the counterflow becomes multivortex. The simulation results are validated with experimental data obtained from Stereoscopic Particle Image Velocimetry and surface oil visualization measurements. © 2018 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 64: 1859–1873, 2018

中文翻译：

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气体涡流单元中二次流的机理

使用经过实验验证的数值模拟研究了盘形气体涡流单元（GVU）中二次流动现象的流体动力学。使用ANSYS FLUENT仿真^®v.14a揭示了沿着中央排气口核心的回流区域的发展，以及该单元盘部分大部分中的逆流多涡旋区域的发展。在测试条件下，发现GVU流量实际上是高度螺旋形的。随着旋流变得更强，二次流动现象逐渐发展。回流区域首先通过排气管路中的涡流衰减机理发展。在GVU端壁附近的边界层中，近壁射流的形成最终导致整个单元的流动逆转。当射流变得更强时，逆流变为多涡流。通过从立体粒子图像测速和地面油可视化测量获得的实验数据验证了仿真结果。©2018 The Authors AIChE Journal由Wiley Periodicals，Inc.出版AIChE J，64：1859–1873，2018