旋风分离器气相旋转流流场动态特性的研究进展

旋风分离器的气相旋转流场对颗粒的分离过程有重要影响。本文指出实验测量和数值模拟表明这种流场具有很强的动态特性，表现为速度和压力随时间的低频高幅脉动变化。但以往的研究主要关注流场的稳态时均特性，缺少对流场动态特性的研究。旋风分离器内流场动态特性主要产生于旋转流的旋转中心围绕着几何中心作随机摆动，由此造成了流动参数的脉动和湍流强度的急剧增大，也导致了对时均流场中一些现象的分析不清晰。此外，由于各种气固分离模型没有考虑流场的动态效应造成了计算结果不够准确。文章指出目前这种流场动态特性主要是实验测量分析，数值模拟方法尚难以准确描述，还需在计算模型上改进。开展流场动态特性的研究对开发高效低阻旋风分离器和改进其分离性能是非常必要的。

Research progress on dynamic characteristics of swirling flow in a cyclone

Gas-phase flow field in a cyclone has an important influence on particle separation process. Both experiment and simulation indicate that the swirling flow has a strong dynamic characteristics, which shows that the flow parameters fluctuate with low frequency and high amplitude. However, the previous studies were mainly focused on the steady state time-averaged characteristics of the flow field, and lack of systematic research on the dynamic characteristics. The main manifestation of the dynamic characteristics of swirling flow is that the center of the swirling flow in a cyclone is deviated from the geometric center, namely the existence of the oscillation of swirling flow, which induces the flow parameter fluctuating and turbulence intensity increasing sharply, also leads to the unclear explain of some phenomena in the time-averaged flow field. Moreover, the dynamic effects of flow field are not taken into account in the gas-solid separation models, as a result, the separation performance calculation is not accurate enough. At present, the dynamic characteristics are mainly analyzed by experimental measurements, and the numerical simulation method is difficult to describe accurately due to the turbulence calculation model. It is necessary to study the dynamic characteristics of the flow field in a cyclone for developing high efficient and low pressure drop cyclone or improving the separation performance.