中文摘要：

旋流喷嘴内超临界流体中沥青溶质的体积分数分布对颗粒成形有重要影响。根据减压相变传质传热理论开发了闪蒸相变模型,采用自定义函数（UDF）的方式植入到CFD软件Fluent中。将闪蒸相变模型耦合多相流混合模型用于研究旋流喷嘴内超临界流体的闪蒸相变过程,分析旋流喷嘴内压力、速度、温度和各相浓度分布,以预测旋流喷嘴对颗粒成形的影响。结果表明,旋流喷嘴内三相介质分层流动,从而实现戊烷溶剂与沥青溶质的预分离,有利于形成粒径较小且密实的沥青颗粒。

英文摘要：

The volume fraction distribution of the asphalt solute in supercritical solution at swirl nozzle obviously affects the particle formation. Based on the theory of heat and mass transfer in phase change caused by abrupt pressure drop,the flash evaporation model suitable for supercritical fluid model was developed and added to Fluent by the UDF method. By using the flash evaporation model coupling with multiphase mixture model the process of the flash evaporation in the swirl nozzles was studied. A detailed analysis of the distributions of pressure, velocity, temperature and concentration of each phase inside nozzle was carried out in order to predict the important effect of swirl nozzle on pellet-forming. Simulation results showed that there was three-phases stratified flow in the swirl nozzle, so as the pre-separation of pentane solvent and asphalt solute was realized, which was conducive to form smaller and more compact particles.