基于OpenFOAM的异戊烷闪蒸喷雾动力学特性研究

Numerical Study on Spray Dynamics of Iso-pentane Flashing Spray Using OpenFOAM

石油、化工等过程工业中,由于压力容器或者管道破裂而容易引发高压危险化学品泄漏形成闪蒸喷雾。掌握这类闪蒸喷雾动力学特性对事故危害的风险评估具有重要意义。本文通过开源库OpenFOAM及网格局部加密技术对异戊烷闪蒸喷雾进行了数值仿真研究。不同喷雾初始压力和过热温度下模拟喷雾形态结果、以及液滴粒径与速度分布,均与高速摄像机拍摄的喷雾图像及相位多普勒粒子分析仪(PDPA)测得的粒径、速度数据吻合良好。初始喷雾压力和温度增加时,异戊烷闪蒸喷雾气化成核强化,使喷嘴出口处雾化破碎程度与径向膨胀更为剧烈,出口锥角扩大,同时成核均匀度增加,液滴SMD降低,喷雾速度增加。但是由于轴向动量减弱,液滴相贯穿长度降低。

The explosive flashing spray may occure during the accidental release of flammable and toxic pressure-liquefied gases in chemical or nuclear industry due to the failure of a vessel or pipe in the form of a small hole.It is quite important to predict the spray dynamics of the flashing spray for the risk assessment of accident hazards.This paper conducted a numerical study on iso-pentane flashing spray by open source C++library OpenFOAM.The numerical results of spray images under different initial pressures and temperatures,and droplet diameter and velocity distribution all agreed with the experimental data well measured by high-speed camera and Phase Doppler Particle Analyzer(PDPA).The results indicated that increasing pressure and superheat degree led to an increase in atomization magnitude,radial expansion,spray angle and droplet velocity at nozzle exit due to the intensive nucleation,while a decrease in droplet Sauter mean diameter(SMD)and penetration distance.It also enhanced the spray uniformity.