T型管油水分离数值模拟及最优分流比的计算

Numerical simulation of the oil-water split performance in the T-shape junction and the way for calculating the optimalized split ratio

采用Euler Euler多相流模型,研究了油水混合物流速0. 55 m/s、不同含油率的工况下,分流比对T型管油水分离效率的影响。结果表明,当油水混合物流速为0. 55 m/s时,油水两相在T型管水平管内流型为带有混合层的分层流(ST&MI),且各层高度受含油率影响。随分流比的增大,依次流入支管的为油层、混合层、水层。含油率分别为25%、44. 4%、73. 5%的工况下,对应的最优分离比分别为0. 353、0. 461、0. 611。含油率对T型管分离效率的影响很大,随含油率增大,T型管的分离效率降低。油滴粒径对T型管分离效率的影响较大,油滴粒径越大越有利于油水混合物的分离。油水混合物的流速越大,T型管的分离效率越低。油水混合物流速对最优分流比几乎无影响。对于常规T型管的油水两相流模拟,可用均一粒径来进行粗糙的定性分析,而采用相群平衡模型可以更准确地定量分析T型管的油水分离效率。

This paper is intended to study the effect of the split ratio at the water-oil separation efficiency of the T-junction under the condition of the oil-water mixture at a rate of 0. 55 m/s in the different oil content rates by using the Euler Euler multiphase flow model. The results of the split show that,when the oil-water mixture flows at the rate of 0. 55 m/s,the 2-phase oil-water flowing rates in the T-junction horizontal pipe can be taken as a stratified current in a form of the mixed layer( ST&MI). The height of each layer can be affected by the oil content rate. With the increase of the split ratio,the oil layer,the mixed layer and the water layer tend to flow into the branch pipe consequently. When the oil content is 25%,44. 4% and 75%,the optimalized separation ratios should be supposed to be 0. 353,0. 461 and 0. 611,respectively. In addition,the oil content has a great influence on the separation efficiency of the T-junction. Under the conditions of the oil content rates of 25%,44. 4% and 73. 5%,the corresponding maximum separation efficiencies can be illustrated correspondingly at 82. 05%,80. 41% and 60. 60%. At the same time,with the increase of the oil content rates,the split efficiency of the T-junction may tend to decrease. Therefore,when the oil content remains at the rate of 44. 4%,the paper would like to do the simulation again by choosing the oil particle sizes respectively of 0. 5 mm,1 mm and 1. 5 mm. The results of our study show that,the bigger the oil droplet size,the higher the split efficiency of the T-junction would be. On the other hand,when the oil content rate stays at 44. 4%,the paper would like to choose the inlet flow rates of 0. 25 m/s,0. 4 m/s,0. 55 m/s,0. 7 m/s and 0. 95 m/s,respectively and then do the simulation again.The results of our seperation practice tends to show that,with the increase of the flowing rates from 0. 25 m/s to 0. 95 m/s,the split or separation efficiency may tend to fall from 86. 74% to76. 84%,in case the split ratio is 0. 45. Therefore,it can be said that,the greater the speed of the oil-water mixture,the lower the separation or split efficiency of the T-junction will be.Nevertheless,the flowing rate of the oil-water mixture has just had little effect on the optimal split ratio. Thus,for the oil-water2-phase flowing simulation of the conventional T-junction, it would be possible to do the qualitative analysis roughly by using the uniform particle size,though more accurate quantitative analysis of the oil-water separation efficiency of the T-junction can be done with the PBM model.