旋风分离器自然旋风长的影响因素

Influence Factors of the Natural Cyclone Length in Cyclone Separators

自然旋风长为旋涡尾端到排气管下口截面的轴向距离。旋涡尾端是复杂的湍流动力学现象,对旋风分离器内颗粒返混、壁面磨损、料腿结垢和堵塞有重要影响。目前,学者们将自然旋风长的影响因素主要归结为筒体直径、入口面积和排气管直径3个方面,忽略了其他结构参数及操作参数的影响,故经验公式的准确性及适用性较差。笔者对旋风分离器内部能量传递过程进行分析,阐述旋涡尾端的存在机理,并实例说明自然旋风长经验公式的局限性与不足,总结了筒体的高/径比、锥体尺寸等几何参数,以及入口速度、入口浓度等操作参数对自然旋风长的影响,以期为旋风分离器高度的设计优化提供参考。

Natural cyclone length is the axial distance between the vortex end and the bottom section of vortex finder. The vortex end is a complex turbulent dynamic phenomenon, which has important influence on particle backmixing, wall wear, fouling and blockage of dipleg in the cyclone separator. At present, the influence factors to the natural cyclone length have been attributed to the body diameter, inlet area and vortex finder diameter. However, the influence of other structural and operating parameters have been ignored, and thus the developed empirical formulas might be not accurate enough for application. This study analyzes the internal energy transfer inside the cyclone separator and describes the mechanism of the vortex end. In addition, an example is provided to illustrate the limitations and shortcomings of empirical formula. Then, the effects of the geometric parameters (e.g. cylindrical height, cone size, etc.), operating parameters (e.g. inlet velocity, etc.) and the inlet concentration on natural cyclone length are summarized. This work can provide an important reference for design optimization of cyclone separator height.