重油催化裂化进料雾化喷嘴出口结构对喷嘴性能的影响研究

Effect of Outlet Structure of FCC Feed Atomizer with Heavy Oil on Nozzle Performance

采用Fluent软件,基于欧拉-欧拉方法的VOF多相流模型对喷嘴的内部流场进行仿真分析,研究喷嘴出口段结构参数对喷嘴性能的影响;在确定喷嘴出口段最优结构的基础上,应用基于欧拉-拉格朗日方法的DPM模型对喷嘴的外部雾化射流区域进行了雾化状态分析,并探究了喷嘴的雾化机制。结果表明:出口锥角θ=51°时喷嘴的性能最优,平均速度为101.19 m/s,湍流强度为2141.1%,达到最大值;出口长度L_(2)=20 mm时喷嘴的性能最优,速度为101.03 m/s,湍流强度为2121%;出口直径d_(2)=25 mm时喷嘴性能最优,平均速度为101.49 m/s,湍流强度为2101%,且出口直径d_(2)对喷嘴的雾化性能影响最大。并根据优化后的结构尺寸进行了5∶1比例缩小的实验,对喷嘴内部液相流动状态呈四点分布进行了验证,同时喷嘴外部雾化液滴分布锥角与仿真结果误差为3.81%,雾化液滴粒径最大误差为3.67%。

The internal flow field of the nozzle was simulated and analyzed based on the VOF multiphase flow model of Euler-Eu⁃ler method with Fluent software.On the basis of determining the optimal structure of the nozzle outlet section,the external atomization jet region of the nozzle was analyzed by using the DPM model based on Euler-Lagrange method,and the atomization mechanism of the nozzle was explored.The results show that the nozzle has the best performance when the exit cone angleθ=51°with the average velocity of 101.19 m/s and turbulence intensity of 2141.1%;the nozzle has the best performance when the exit length L_(2)=20 mm with the ve⁃locity of 101.03 m/s and turbulence intensity of 2121%;the nozzle has the best performance when the outlet diameter d_(2)=25 mm and the average velocity is 101.49 m/s and the turbulence intensity is 2101%,and the outlet diameter d_(2) has the greatest influence on the atomization performance of the nozzle.According to the optimized structure size,a 5∶1 scale reduction experiment was carried out to verify the four point distribution of the liquid phase flow in the nozzle.Meanwhile,the error between the cone angle of the atomized droplet distribution outside the nozzle and the simulation result is 3.81%,and the maximum error of the atomized droplet size is 3.67%.