基于VOF-DPM耦合的Y型喷嘴雾化研究

Atomization performance of Y-jet nozzle based on VOF-DPM coupling method

采用VOF-DPM(流体体积-离散相模型)耦合方法的数值模拟,研究液体黏度对Y型喷嘴内流动和喷嘴雾化性能的影响。首先对Y型喷嘴内部和外部区域进行多面体网格划分,并借助基于气液体积分数值的自适应网格加密技术有效提高气液界面识别精度。分析喷嘴内流动与喷嘴外雾化的关联,研究液体黏度对雾化性能的影响。结果表明:重油黏度较高,流速较小,喷嘴内重油不易被气体吹散和掺混,液体雾化较难。柴油密度低于重油,易被加速,导致喷雾贯穿距离大于重油,雾化更容易,柴油的喷雾锥角与重油差距不大。重油的喷雾索特平均直径d s为137.14,略高于柴油d s约0.8%。研究对评估燃烧器燃烧性能及其适应多种燃料的改造设计具有重要的应用价值。

The effects of liquid viscosity on the flow and atomization performance of Y-jet nozzles were studied by using the VOF-DPM coupling method.Firstly,the internal and external environmental areas of the Y-jet nozzle were divided into polyhedral grids,and the accuracy of gas-liquid interface recognition was effectively improved using adaptive grid refinement technology based on gas-liquid integral values.The correlation between the flow inside the nozzle and the atomization outside the nozzle was analyzed,and the effects of liquid viscosity on atomization performance were studied.The results show that the viscosity of heavy oil is high,the flow rate is small,and the heavy oil in the nozzle is not easily dispersed and mixed by gas,making it difficult to atomize the liquid.The density of diesel oil is lower than that of heavy oil,which is easy to be accelerated,leading to the penetration distance of spray is greater than that of heavy oil,which makes atomization easier.The spray cone angle of diesel oil is close to that of heavy oil.The d s of heavy oil is 137.14,slightly higher than the d s of diesel by about 0.8%.The result has important application value for evaluating the combustion performance of burners and their adaptability to various fuel modification designs.