并联旋风分离器的旋流稳定性分析

Analysis on Stability of Vortex Flow in Parallel Cyclones

分别选用2台和4台直径300 mm的相同PV型旋风分离器作为分离元件,共用进气管、集气室和排尘室,以中心对称方式组成两种并联分离器,并通过数值模拟比较单分离器与两种并联方案中各分离元件气相流动的特点.气体介质为常温常压空气,入口气速15?30 m/s.结果表明,2台或4台并联时各分离元件流量偏差分别不超过0.35%和0.28%,压降最大偏差为0.79%和0.43%,流量分配均匀,灰斗内窜流返混不明显,且4台并联时效果更好.4台并联时分离元件排尘段的稳定性指数比2台并联或单分离器降低过半,旋流稳定性显著增强.对称排列的分离元件在公共灰斗中会形成具有自稳定性的对称涡系,对分离元件内旋进涡核的摆动有约束作用,旋流稳定性增强.

To study the gas flow behavior in parallel cyclones, two kinds of parallel cyclones, consisting of 2 and 4 identical cell cyclones（model PV with a barrel diameter of 300 mm） respectively, were numerically simulated with Fluent. The cell cyclones were axial-symmetrically arranged and shared an inlet pipe, an upper gas chamber and a dust hopper. The gas medium was atmospheric air with the inlet velocity of 15？30 m/s. The total flow fields were compared between cell cyclones and a single cyclone. The results show that the difference of flowrate between cell cyclones does not exceed 0.35% for 2 cyclones and 0.28% for 4 cyclones both in parallel, and the maximum difference of corresponding pressure drop is not more than 0.79% and 0.43%, which means the flow is evenly distributed in all cell cyclones. Cross flow does not appear in the common dust hopper. For 4 cyclones in parallel, the stability index of vortex flow in each cell cyclone is below half of that in a single cyclone. Theoretical analysis on axial-symmetrically arranged point vortices indicates that the higher stability is ascribed to the inherent property of vortex system, which effectively weakens the sway of precessing vortex core in cell cyclones. There are favorable effects on particle separation in axial-symmetrically arranged parallel cyclones.