Abstract:

The novel multi-rotor gas-liquid vortex separator can realize the high-efficiency separation of gas-liquid cyclone in the large-diameter separator. The inlet vortex head is one of the critical components of the separator. The droplet size distribution and the pre-separation performance of the vortex head were investigated in a large-scale cold separator model. The initial droplet size distribution is rapidly redistributed under the high-speed airflow in the straight inlet pipe. The redistribution feature is similar to the Gaussian distribution with the Sauter mean diameter (SMD) is 16.8 μm. The droplets move stably in the straight inlet pipe with H/D = 2.47—8.48 at the gas velocity of 16.95 m/s, and the particle size distribution does not show apparent changes. At high gas velocity, the combined action of the shear effect and wall effect increases SMD slightly. The droplet size distribution changes significantly when the droplets flow through the vortex arms, showing the “double peak”. The impact of the vortex arms on the droplet aggregation is noticeable. Based on the particle size distribution analysis, the droplet characteristics at the end of vortex arms are obtained. It is found that the pre-separation performance of the vortex head is superior. When the pressure drop is only 3.2%—8.4% of the total pressure drop, the separation efficiency can be 42.8%—62.5% of the total separation efficiency. The inlet swirl head structure can not only create a strong swirling initial separation environment for the mixed phase, but also realize the inertial pre-separation of the mixed phase with its own structural characteristics.

Key words: inlet structure, particle size distribution, separation, multiphase flow

摘要：

新型多旋臂气液分离器可实现大直径分离器内的气液旋流高效分离，其入口旋流头结构是分离器的重要组件之一。通过大型冷模实验，对入口旋流头结构的液滴群粒径分布进行非引出式在线测量，从压降和分离效率角度考察了旋流头的预分离性能。结果表明，在入口直管段，初始液滴粒径会在高速气流的作用下迅速进行重新分布，粒径分布呈类正态分布，Sauter平均粒径（SMD）为16.8 μm。在16.95 m/s的气速下，液滴群在H/D=2.47~8.48长度内的入口直管段中运动状态稳定，粒径分布未发生明显变化。在高气速的操作条件下，剪切效应和边壁效应共同作用使SMD略有增大。液滴群在流经旋流臂后，粒径分布发生显著变化，出现“双峰”特征，旋流臂对液滴的聚集效果明显。通过粒径分布分析，预测了旋流臂末端的液滴特征。发现旋流头的预分离性能优越，在压降占比仅3.2%~8.4%的情况下，分离效率占比可高达42.8%~62.5%。入口旋流头结构不仅可以为混合相创造强旋流的初始分离环境，还能借助自身结构特点实现对混合相的惯性预分离。

关键词: 入口结构, 粒度分布, 分离, 多相流