双支T形管内油滴聚结破碎特性分析

Analysis of Oil Droplet Coalescence and Breakage Characteristics in Double Branch T Junction Pipe

现有研究未对T形管内油滴的聚结破碎情况做进一步分析,且采用PBM模型研究双支T形管内油滴聚结破碎特性的研究尚未见报道。为此,采用CFD-PBM耦合方法对双支T形管内油滴聚结破碎行为及分离特性进行数值模拟分析,同时开展室内试验对模拟结果的准确性进行验证。研究结果表明:T形管支管内的油滴粒径大小受湍动能变化影响较大,湍动能由0.64 m^2/s 2减小到0.36 m^2/s 2时,油滴粒径由300μm增加到460μm,呈聚结状态,而湍动能由0.36 m^2/s 2增大到0.60 m^2/s 2时,油滴粒径由480μm降低到360μm,呈破碎状态;随支管高度的增加,其内部湍动能逐渐减弱而油滴粒径却逐渐增大;靠近入口的支管Ⅰ内部油相体积分数明显大于支管Ⅱ,且同一支管内左侧的油相体积分数也高于右侧;双支T形管的分离效率随支管出口分流比的增大呈先升高后降低的趋势,当分流比为50%时,分离效率达到最大值30.2%;最佳分流比条件下,处理量在2~4 m^3/h范围内变化时,T形管的分离效率呈逐渐降低趋势,由32.5%降低到25.0%。研究结果可为T形管结构的优化设计提供一定的理论指导。

Existing studies do not further analyze the coalescence and breakage of oil droplets in T junction pipe,and the study on coalescence and breakage characteristics of oil droplets in double-branch T junction pipe using PBM model has not been reported.To address the problem,the CFD-PBM coupling method is used to perform numerical simulation analysis on coalescence and breaking behavior and separation characteristics of oil droplets in double-branch T junction pipe.At the same time,laboratory experiments are conducted to verify the accuracy of the simulation results.The results show that the size of the oil droplets in the branch of the T junction pipe is greatly affected by the turbulent kinetic energy.When the turbulent kinetic energy decreases from 0.64 m^2/s 2 to 0.36 m^2/s 2,the particle size of the oil droplets increases from^300μm to 460μm.The oil droplets are in coalescence state.When the turbulent kinetic energy is increased from 0.36 m^2/s 2 to 0.60 m^2/s 2,the oil droplets have reduced particle size from 480μm to 360μm,and are in broken state.With the increase of the height of the branch pipe,the internal turbulent kinetic energy gradually weakens while the oil droplet particle size gradually increases.The volume fraction of the oil phase in branch I near the inlet is significantly larger than that in branch II.The volume fraction of the oil phase on the left side in the same branch is higher than that on the right side.The separation efficiency of the double-branch T junction increases first and then decreases with the split ratio of the branch outlet.When the split ratio is 50%,the separation efficiency reaches the maximum value of 30.2%.Under the optimal split ratio,when changing the process capacity within the range of 2~4 m^3/h,the separation efficiency of the T junction pipe shows a gradual decrease trend from^32.5%to 25.0%.The study can provide theoretical guidance for the structural optimal design of the T junction pipe.