旋风分离器内颗粒质量浓度分布数值模拟

Numerical simulation of particles mass concentration distribution in cyclone separator

采用颗粒随机轨道模型和单元内颗粒源法,对旋风分离器内不同粒径颗粒质量浓度分布进行了数值模拟。结果表明,粒径较小的颗粒(dp≤4μm)大部分在旋风分离器分离空间锥段进行分离,而较大颗粒(dp>4μm)大部分在环形空间与分离空间筒段即被分离。随着颗粒粒径增加,分离器外壁的颗粒质量浓度逐渐呈螺旋灰带分布,内旋流夹带减小,环形空间顶板下方出现顶灰环。升气管入口0.25D(筒体直径)附近的短路流对小颗粒的影响较大。在分离空间下部排尘口附近0.5D有明显的颗粒返混,返混量随着颗粒粒径增大而减少。

The different diameter particles mass concentration distribution in a volute cyclone separator was numerically simulated by using Lagrange approach and Particle-Source-in-Cell method. The results show that most of smaller particles （dp≤4μm） are separated in cone section, while most of bigger particles （dp〉4μm） are separated in annular space and cylinder section of separation space. With the increase of particle diameter, the inner vortex particle entrainment decreases, and a helix dust strand near the cyclone wall and a dust ring under the top plate of the cyclone for larger particles are observed. The shortcut flow is detected below the vortex finder 0.25D （cyclone diameter）, which has a big influence on the smaller particles. Serious particle backmixing is observed above the dust discharge 0.5D and it decreases with the increase of particle diameter.