喷雾干燥制备CL-20过程中喷嘴直径对液滴雾化行为影响的CFD模拟

CFD Simulation of the Effect of Nozzle Diameter on Droplet Atomization Behavior During Spray Drying Preparation of CL-20

为研究喷雾干燥法制备六硝基六氮杂异伍兹烷(CL-20)过程中不同喷嘴直径下干燥塔内液滴的雾化特性,利用Fluent软件建立了喷雾干燥塔数学模型,研究了不同工艺参数(液体流量、气体流量、气体温度和溶剂)下,喷嘴直径对干燥塔内液滴索特平均直径(D_(32))的影响.模拟结果表明:喷嘴直径一定时,随着液体流量的增加,液滴的D_(32)增加,且液体流量为1.5 mL·min^(-1)的液滴雾化效果最好;随着气体流量的增大,液滴的D_(32)减小,且气体流量为7883 mL·min^(-1)的雾化效果最好;随着气体温度的升高,液滴的D_(32)先减小,当气体温度超过溶剂沸点时开始增大,气体温度分别为333 K(丙酮)和353 K(乙酸乙酯)时的D_(32)最小;在液体流量、气体流量、气体温度和溶剂不变的情况下,D_(32)随着喷嘴直径的减小而减小,且直径为0.5 mm的液滴雾化效果最好;在最佳条件下,溶剂为丙酮的D_(32)(0.31μm)小于溶剂为乙酸乙酯的D_(32)(0.44μm).

In order to study the effect of different nozzle diameters on droplet atomization characteristics during preparation hexanitrohexaazaisowurtzitane(CL-20)in a spray drying tower,a mathematical model of the spray drying tower using Fluent software was established.The effect of nozzle diameter on Sauter mean diameter of droplet(D_(32))at different process parameters(liquid flow rate,gas flow rate,gas temperature and solvent)were studied.The simulation results show that when the nozzle diameter is constant,with liquid flow rate increasing,D_(32) increases,and the best atomization performance is at liquid flow rate of 1.5 mL·min^(-1);with gas flow rate increasing,D_(32) decreases,the best atomization performance is at gas flow rate of 7883 mL·min^(-1).D_(32) firstly decreases with the increase of gas temperature,and then increases when it exceeds the boiling point of solvent,and the D_(32) is smallest at temperature of 333 K(acetone)and 353 K(ethyl acetate).At constant liquid flow rate,gas flow rate,gas temperature and solvent,D_(32) decreases with the decrease of nozzle diameter,and the nozzle with the diameter of 0.5 mm has the best atomization performance.At the best conditions,the D_(32) of is acetone(0.31μm)smaller than that of ethyl acetate(0.44μm).