旋风分离器内颗粒质量浓度分布数值模拟

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。

Numerical simulation of particles mass concentration distribution in cyclone separator

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≤4 μm) are separated in cone section,while most of bigger particles(dp>4 μm) 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.