旋风分离器流场数值模拟及其涡结构识别

采用计算流体力学软件Fluent,基于非稳态雷诺应力湍流模型对旋流分离器流场进行了模拟,得到了旋流分离器内部切向速度和轴向速度分布,并与实验值进行对比;同时将Q判据应用于旋风分离器内漩涡结构的识别,比较了切向进口处两种不同网格结构对涡结构的影响。结果表明:非稳态的雷诺应力湍流模型模拟结果对切向速度进行很好的预测,几乎与实验一致,轴向速度与实验结果趋势一致,能够很好的预测轴向速度的"驼峰"结构;切向进口处的网格质量由于伪扩散对模拟结果有影响,需要进行优化;利用Q判据能够将旋风分离器内部的旋进涡及环形空间二次涡进行准确识别,在旋风分离器中心轴线附近及环形空间存在漩涡。

Numerical simulation of the flow field in a cyclone separator and vortex identification

The flow field in a cyclone separator was simulated with the unsteady RSM turbulence model by using the CFD software Fluent.The tangential and axial velocity distributions inside the cyclone separator was got and compared with the experiment results.Vortex identifications was employed to distinguish the actual various vortices in cyclone separator with the consideration of two kinds of meshing structures at the tangential inlet zone.It was found that the unsteady RSM model has a good performance in the simulation of the cyclone separator.The tangential velocity consistent well with the experimental result and the ‘Hump structure’ of axial velcotiy is predicted.to the false diffusion.The mesh at the tangential inlet of cyclone separator has a great effect on the simulation result by analyzing the false diffusion.The Qvortex identification can be employed to distinguish the swirling flow around the axis and the secondary eddies in the annular space of cyclone separator.