入口含尘浓度变化对不同排气管结构PV型旋风分离器分离效率的影响

旋风分离器的入口浓度对其分离效率和压降有重要影响。在入口气流含尘浓度5～550 g/m3范围内，采用325目滑石粉，对直径500 mm的PV型旋风分离器进行了分离效率的实验测定，其中排气管的结构采用直筒型(A型)，锥口型（B型）和大直筒型（C型）3种结构。实验结果表明，3种结构排气管旋风分离器分离效率均随入口浓度的增加而增加，当入口浓度大于150 g/m3时，分离效率上升幅度开始趋于平缓。旋风分离器入口浓度增加一方面使切向速度降低，分离能力下降，但另一方面使颗粒之间的团聚作用增大，惯性分离能力增大，分离效率增加，综合作用结果是分离效率提高，但逃逸颗粒的绝对量增大。实验结果也表明，排气管的结构对旋风分离器的效率影响较大，尤其是排气管直径，基于实验结果给出了入口浓度变化时旋风分离器分离效率的计算公式 ，该计算公式综合考虑了入口速度和排气管直径的影响。

STUDY OF EFFECT OF FEED DUST CONCENTRATION ON SEPARATION EFFICIENCY OF PV TYPE CYCLONE WITH DIFFERENT EXIT TUBES

The feed dust concentration has an important influence on the separation efficiency and pressure drop of cyclone. In the range of dust concentration of 5~550 g/m3, the separation efficiency of 500mm diameter PV cyclone with three different exit tubes was investigated using 325 mesh talcum powder. The exit tubes with small cylindrical (type A), cone (type B) and big cylindrical (type C) were used, respectively. The experimental results show that the separation efficiencies go up with increasing dust concentration in feed. However the separation efficiency increases smoothly when the feed concentration is above 150 g/m3. With increasing the feed concentration, the tangential velocity decreases and thereby the separation ability decreases. As the aggregation between particles increases, the inertia separation ability rises, resulting in improved separation efficiency but more particles escaped. The experimental results also show that the exit tube structure of cyclone separator, especially the diameter, has a considerable effect on separation efficiency. Finally, according to the experiment date and considering the influence of inlet feed velocity and exit tube diameter, an empirical equation for calculating separation efficiency of cyclone is given.