Numerical investigation on particles separation using an enhanced cyclone with shunt device: Effect of vortex finder lengths

Abstract

To improve the performance of the enhanced cyclone with shunt device (ECSD), the vortex finder lengths optimization for the ECSD is carried out by numerical investigation. Reynolds stress model and discrete phase model are adopted. The results show that the separation ability of the ECSD can be improved by longer vortex finder, which is contrary to the generally accepted conclusion that the vortex finder length of the traditional cyclone should not be longer than cylindrical section length. When the ratio of vortex finder length to cylindrical section length reaches 1.5 (225 mm vortex finder), the total separation efficiency, reduced separation efficiency and comprehensive separation efficiency are 90.7%, 89.7%, and 80.6%, respectively, which are the highest. The tangential velocity distribution is one of the most important reasons that the separation efficiency increases with the increase of the vortex finder length in general. The tangential velocity in the conical section of the ECSD increased with the increase of vortex finder length. When the length of vortex finder is the same as that of cylindrical section, the overall energy consumption and split ratio of the ECSD are the largest of 1.88 kPa and 12.4%, respectively, which is detrimental to the overall performance of ECSD.