Studyon Preparation Technology Of Spherical Propellant Basedon Microfluidic

The propellant is loaded in the cartridge boring of the gun body,and the initial kinetic energy is provided for the final firing by the energy generated by its own combustion.With the rapid development of the military field,gun barrel weapons have higher requirements on the firing speed of propellant.Due to the relatively complex structure and long molding time of barrel weapons,it is easier to improve the charging density by improving the drug preparation technology than by using high-energy gunpowder or changing the structure of barrel weapons.The combustion performance of the drug can be improved by changing the shape of the drug,increasing the combustion area,increasing the stacking density,increasing the compactness and improving the uniformity of the drug.The common method of preparing spherical propellant is mechanical stirring,which is dispersed into balls by the surface tension of liquid drops.The instability of external force will directly affect the monodispersity of particle size.In this paper,by combining with microfluidic technology,the uniformity of particle size can be controlled,the sphericity is high and stable,and the continuous and uniform production can be realized.Mainly responsible for the following work:(1)The droplet forming process was studied according to droplet related theories,and the process was numerically simulated and analyzed by COMSOL software.The formation process of liquid droplets in T and cross structures was studied,and the influence of chip size,wall wettability and flow rate ratio on the formation of liquid droplets was explored,so as to determine the key conditions for the preparation of spherical drugs.(2)PMMA was used as the substrate of the chip and CO2 laser etching technology was used to prepare microfluidic chips.Two types and two sizes of microfluidic chips were prepared by adjusting the etching power and speed of the laser.(3)The wall conditions for the preparation of oil-in-water droplets were determined by the simulation results,the PMMA chip surface was modified with PVA solution,and the stability of the modified results was investigated,including the treatment time of the chip by the solution and the chip placement time after treatment.A self-made contact Angle measuring device was used to observe the contact angles of water at different time nodes,and the contact Angle plug-in of ImageJ software was used to measure the contact angles of water at different time nodes.(4)The prepared microfluidic chip was modified according to the optimal modification method.The modified chip was filled with the solution of the continuous phase(water phase)and the dispersed phase(oil phase)with a good ratio,and the experimental process was filmed.The effect of flow rate on droplet size was investigated by measuring droplet size in Photoshop and adjusting the flow rate.