下段扩容式旋风分离器分离性能的数值模拟

Numerical Simulation on Separation Performance of a Cyclone Separator with an Expanded Volume at the Bottom

为了提高传统旋风分离器的分离效率,提出了一种下段扩容式旋风分离器。采用数值模拟方法分析了扩容段最大直径对该旋风分离器分离性能的影响,并与传统旋风分离器进行对比。结果表明:分离器设置下部扩容段能够有效增大外旋流区的面积,减少分离器底部的颗粒返混现象;在扩容段高度相同的条件下,随着扩容段最大直径的增大,分离器进出口压降逐渐减小,粒径20μm及以下煤粉的分离效率先提高后降低,粒径20μm以上煤粉的分离效率逐渐降低;当扩容段最大直径为1.30D(D为筒体直径)时总分离效率达到最高值90.03%,比传统旋风分离器的总分离效率高4.4%。

To improve the separation efficiency of traditional cyclone separators, a new type of separator with an expanded volume at the bottom was proposed. The influence of the diameter of volume-expanded section on the separation performance of the separator was studied by numerical simulation, which was subsequently compared with that of a traditional separator. Results show that the bottom expanded section can effectively increase the outer vortex area and reduce the back mixing phenomenon of particles at the bottom of the separator. With rising diameter of the expanded section, the pressure drop between inlet and outlet of the separator decreases gradually under the same height of the expanded section, the separation efficiency of pulverized coal with particle diameters less than or equal to 20 μm firstly increases and then decreases, while the separation efficiency of pulverized coal with particle diameters greater than 20 μm decreases gradually. The general efficiency could reach the highest value of 90.03% when the diameter of the expanded section is 1.30D, which is 4.4% higher than that of a traditional cyclone separator.