双场耦合破乳脱水装置中乳化油液滴聚结与破碎的数值分析

针对依靠单一的破乳方法或手段，难以对乳化油进行有效地脱水净化处理的问题，运用一种集成电场破乳和旋流离心脱水于一体的双场耦合破乳脱水装置，使油中液滴在电场中聚结增大，在旋流离心场的作用下快速实现油-水分离。由于乳化油中液滴在双场耦合装置中的动态聚结和破碎，对装置的油-水分离性能影响较大，且过程复杂，通过电聚结核函数和破碎核函数，建立群体平衡模型，模拟了双场耦合脱水装置中乳化液滴的聚结和破碎。计算结果表明：外加电压对液滴聚结产生重要影响，随着电压升高，液滴平均粒径和分离效率先增大，随后保持稳定；当U=11 kV时，相对于无电场条件，液滴平均粒径增大了60%，分离效率提高了27.5%；较低的入口流速虽对液滴聚结有利，但降低了油-水在装置中的分离效果，因此存在最佳入口流速。计算结果对装置参数设计与选择具有较好的指导意义。

Simulation on the Coalescence and Breakup of Droplet in Double Field Coupling Demulsification and Dewatering Device

It is difficult to achieve effective dewatering of emulsion oil by a single method or unit. A double-field coupling demulsification and dewatering device, which integrates electric field and swirling centrifugal field is used. Droplets coalesce and grow in the electric field and then are separated rapidly under the swirling field. The dynamic coalescing and breaking of the droplets in the emulsified oil in the two-field coupling device have a great influence on the oil-water separation performance, and the process is complicate. The population balance model was established by using electro coalescence and breakup functions to simulate the coalescence and breakup of droplets. The results show that external voltage has a significant effect on the droplet coalescence. With the increase of the voltage, the average droplet size and separation efficiency first increase and then remain stable. Compared with the case of no electric field, the average droplet size and separation efficiency are improved by 60% and 27.5% when the voltage is 11kV, respectively. Although lower inlet velocity is beneficial to droplet coalescence in the electric field, it reduces the separation effect. The employed model has a great significance for the design and selection of device parameters.