Simulation Study On Atomization Behavior Of CL-20 Prepared By Spray Drying

With the development of science and technology,the requirements for energetic materials properties become more and more high,especially high-energy and insensitivity.Studies at home and abroad have shown that the spray drying method has the advantages of short drying time,good heat and mass transfer performance and continuous production.The former should be used in the pharmaceutical,pharmaceutical and chemical industries.CL-20 is the energetic compound with the highest energy density and the best application prospect,but its application is limited because of its high sensitivity.Some researchers try to prepare CL-20 by spray drying method,so as to change its performance.However,the matching relationship between the flow field and the properties of CL-20 is difficult to be established during the experimental process,it is difficult to control the performance of CL-20.Using CFD simulation to study the atomization process of CL-20 prepared by spray drying method can not only reveal the flow field information inside the spray drying tower and the influence of operating conditions on its atomization characteristics,but also optimize the process conditions of the prepared energetic materials.The main contributions of this thesis are as follows:（1）Transport continuity process,particle motion process and realizable k-ε turbulence model and DPM model,were used to establish the CFD model of atomization behavior of CL-20 prepared by spray drying,and the droplet atomization behaviors of CL-20 prepared by spray drying were numerically simulated.（2）Based on the model,the effects of different solvents（acetone,ethyl acetate,acetonitrile and N,N-dimethylformamide）on the temperature field,velocity field and residence time of particles in spray drying tower were analyzed,and the flow field information of atomization flow field of CL-20 prepared by spray drying was obtained by simulation.（3）The variation of the average diameter of atomized droplets under different experimental conditions（temperature,volume flow,feed rate and solvent）was studied by CFD.（4）Based on CFD simulation results,the empirical correlations of the average droplet size were established,and the effects of different operating conditions on the average droplet size and particle size distribution are analyzed,which provide a theoretical basis for the quantitative calculation of droplet size and its distribution.This study not only provide a simulation method for droplet atomization in spray drying process,but also lays a theoretical foundation for performance evaluation and optimization design,especially fot the droplet average particle size and distribution.It is of great significance for theroy guide and practicle applation to prepare other energetic materials by spray drying.