不同结构的旋风分离器二次涡的数值模拟和分析

Numerical Simulation and Analysis of Secondary Vortex in Different Cyclone Separators

以Stairmand旋风分离器、扩散式旋风分离器和环流式旋风分离器为研究对象,采用CFD软件Fluent提供的湍流雷诺应力模型(RSM),研究了内部构件对旋风分离器内二次涡的影响,模拟结果表明:环流式旋风分离器内部导流件有效降低了"上灰环"和"短路流",与另两种旋风分离器相比,筒体顶盖及排气管附近二次涡速度分别从23.6和32.1 m×s^(-1)降至10.2和25.7 m×s^(-1),湍动强度分别由2.38%和3.41%减弱到1.61%和2.39%,筒体顶盖涡流尺度的比例因数由0.25减小为0.11。扩散式旋风分离器的反射屏对于削弱"二次扬尘"现象和"颗粒夹带"的影响效果显著,与Stairmand旋风分离器相比,排尘口附近二次涡速度由25.1降至7.3 m×s^(-1),尺度的比例因数、湍动强度均显著降低。结果表明通过合理的增设内部构件对分离器内流场进行导流,可降低二次涡对于流场的影响。

Effects of internal components on secondary vortex in cyclone separators were simulated by Fluent software using Reynolds stress model（RSM）. Stairmand cyclone separator, diffusible cyclone separator and circumfluent cyclone separator were used as the investigation objects. The results show that the internal deflector of the circumfluent cyclone separator can effectively reduce ＂upper dust ring＂ and ＂short circuit flow＂ effects when compared with the other two cyclones. The velocities of secondary vortex at the top of the cylinder and the exhaust pipe are reduced from 23.6 m×s^（-1） and 32.1 m×s^（-1） to 10.2 m×s^（-1） and 25.7 m×s^（-1）, respectively, while the turbulence intensity is reduced from 2.38% and 3.41% to 1.61% and 2.39%, respectively. The eddy scale factor at the top of the cylinder is reduced from 0.25 to 0.11. Reflective screen in the diffusible cyclone separator can significantly reduce ＂secondary dust＂ and ＂particle entrainment＂ effects, and the velocity of secondary vortex at the discharge port is reduced from 25.1 m×s^（-1） to 7.3 m×s^（-1） when compared with Stairmand cyclone separator. The scale factor and the turbulence intensity of the vortex are significantly reduced. The research shows that the influence of secondary vortex on the flow field can be reduced by rationally adding internal components to divert flow fields in the separator.