入口颗粒浓度对旋风分离器压力降影响的实验分析

An Experimental Study of Feed Concentration Effects on the Pressure Drop of Cyclone

旋风分离器的入口气流颗粒浓度对旋风分离器的压力降有重要影响。在入口气流颗粒质量浓度5~550g/m3范围内,对蜗壳式旋风分离器的压力降进行了实验分析。结果表明,随着入口颗粒浓度的增加,旋风分离器的压力降逐渐降低,尤其是开始阶段,降幅明显。除旋风分离器的入口部分压力损失外,旋风分离器的压力降主要由气、固两相流与器壁之间的摩擦损失和气、固两相流的旋转损失两部分构成,前者与入口气流速度有关,后者与旋转速度有关。随着入口颗粒浓度的增加,摩擦损失部分增加,但旋风分离器内的气、固两相流的旋转速度降低,旋转损失部分降低,综合结果是旋风分离器的总压力降降低。旋风分离器的压力降变化也使管路系统压力分布发生变化,导致入口流量发生变化,加入颗粒后通过旋风分离器的流量相对纯气相时的流量明显增加。最后,给出了入口气流颗粒浓度对旋风分离器压力降影响的计算方法。计算中考虑了加入颗粒后对切向速度的衰减作用,适用于高入口颗粒浓度的工况。

The feed concentration is the main parameters influencing the performance of cyclone. With the feed mass concentration range of 5--550 g/m3, the experiments were conducted in the cyclone with a volute inlet for measuring pressure drop. The experimental results showed that the pressure drop decreased as feed concentration increasing, especially, at the beginning of experiment. In addition to the expansion loss at the cyclone inlet, the pressure drop is mainly composed of two parts, the friction loss of gas-solid surface in the separation zone depending on tangential velocity, surface area and friction coefficient, and the dynamic dissipation loss in the vortex finder determined by tangential velocities and mean axial velocity in the vortex finder. With the increase of feed concentration, the tangential velocities were reduced due to friction loss, resulting in the pressure going up in the vortex finder, which may be the reason that the pressure drop was reduced. The change of pressure drop in cyclone separator led to the inlet flow rate varying, as a consequence of which, the inlet flow rate increased significantly with an increase of feed concentration. Finally, a formula for calculating pressure drop of cyclone was developed based on the Muschelknautz model, considering the particle effects on the tangential velocity, which is suitable for predicting pressure drop under the condition of high feed concentration.