矩形进料体高宽比对旋流器流场和分离性能影响的数值模拟

横截面为矩形的进料体比圆形的分离性能更好,但是一直没有找出矩形进料体合适的高宽比。本文采用数值分析法研究了矩形进料体的高宽比对直径为75 mm旋流器分离性能的影响,将数值结果与Hsieh经典试验结果进行了对比,发现两者有良好的一致性,验证了该方法的有效性。探究了进料体不同高宽比下的压力场、速度场、湍流场和分离效率。结果显示压力降和切向速度随着高宽比的增加出现先增加后减小的趋势,在高宽比为3.0时最大且短路流量最小。因此,可以通过改变高宽比来减小湍动能,随着高宽比的增加,湍动能先减小后增加,在高宽比为3.0时,湍动能最小,继续增加高宽比湍动能变大。采用较大的高宽比可以提高分离精度和减小切割粒径,获得更好的产品质量。对于直径为75 mm旋流器来说,矩形进料体的最佳高宽比应该在3.0~4.0之间,为以后设计合理的进料体结构提供依据。

Numerical simulation of the effect of height width ratio of rectangular feed body on the flow field and separation performance of hydrocyclone

The feed body with rectangular cross-section has better separation performance than the circular feed body,but the suitable height width ratio of the rectangular feeder has not been found.The numerical analysis method was used to study the influence of the height width ratio of the rectangular feed body on the separation performance of the hydrocyclone with a diameter of 75 mm.The numerical results show good agreement with the classic experimental results of Hsieh after comparison,which verified the effectiveness of the method.The pressure field,velocity field,turbulent flow field and separation efficiency under different aspect ratio of feed body were investigated.The results show that the pressure drop and tangential velocity increase at first and then decrease with the increase of aspect ratio.When the aspect ratio is 3.0,the pressure drop and tangential velocity are the largest and the short-circuit flow is the smallest.The turbulence kinetic energy can be reduced by changing the aspect ratio.With the increase of the aspect ratio,the turbulence kinetic energy first decreases and then increases.When the aspect ratio is 3.0,the turbulence kinetic energy is the smallest,and the turbulence kinetic energy becomes larger when continuing to increase the aspect ratio.By using a larger aspect ratio,the separation accuracy can be improved and the cutting particle size can be reduced,and better product quality can be obtained.For a 75 mm diameter hydrocyclone,the optimum height width ratio of the rectangular feed body should be between 3.0 and 4.0,which provides a basis for the design of a reasonable feed body structure in the future.