基于实验的孔板节流后分散相粒径估值模型研究

Experimental Study on Modeling of Dispersed Phase Droplet Size after Orifice Plate Throttling

节流后分散相液滴粒径的准确估值是研究低剪切节流阀的关键,然而现有节流后液滴粒径估值模型的计算结果差异较大,迄今缺乏估值精度和适用性评价等方面的专门研究。文章通过孔板节流室内实验,分析了现有湍流场内液滴破碎后粒径估值模型的精度和适用性;讨论了分散相液滴单次节流后最大粒径与多次节流后稳定粒径间的对应关系;提出了不设实验常数的液滴单次节流后粒径估值模型。结果表明:现有液滴粒径估值模型含有与分散相黏度相关的实验常数,缺乏普适性;在考察的分散相粒径范围内,液滴单次节流后最大粒径为多次节流后稳定粒径的2.74倍;当入口分散相粒径远小于节流孔孔径时,所提出的估值模型计算得到的粒径值与实测d95粒径间平均误差不大于17.2%。

Accurate prediction of droplet size in choke valves is important for the study of low-shear choke valves.However,current prediction models are lack of consistent with few studies on evaluation of accuracy and applicability of these models.The accuracy and applicability of prediction models for dispersed phase droplet size was discussed in this study by restriction orifice experiments.The relationship between maximum droplet size after a restriction orifice and stable droplet size after multiple restriction orifices were discussed.A prediction model without experimental constant was proposed which could be used to calculate droplet size after a restriction orifice.The results show that the applicability of the existing prediction models is limited due to their experimental constants related to the viscosity of dispersed phase.The results indicate that the maximum droplet diameter after a restriction orifice is2.74times of that of the stable droplet size after multiple throttling.When the inlet droplet size is far less than the orifice diameter,the average error between the droplet size calculated by proposed model and the measured d95is less than17.2%.