Preparation Of The Spherical Propellants Based On The Microfluidic Technology

The key to solve the large deviation of the ballistic performance of the medium and small caliber weapon is the preparation of high quality spherical propellants with uniform particle size,controllable size and uniform structure.It is difficult for the present preparation technology to generate the spherical propellants with controllable size and uniform particle size.Therefore,the single spherical propellant and the double spherical were prepared by the microfluidic technology in this research,respectively.The main research contents are as follows:(1)The preparation and characterization of the single spherical propellant.The effects of the flow rate ratio of continuous phase and disperse phase and the nitrocellulose/solvent ratio on the preparation of the single-based spherical propellants were studied by the micro-channel device,respectively.The particle size distribution of spherical propellants were characterized by laser particle size analyzer and image analysis.The surface morphology and internal structure were characterized by SEM.Results showed that when the flow rate ratio of the water-oil phase was fixed to 1000μL/min: 100μL/min and the nitrocellulose/solvent ratio was from 50: 2.0 to 50: 3.0,the stable oil droplets were prepared in the micro-channel.The single-based spherical propellants with the size from 250μm to 350μm were obtained after curing and drying.These single-based spherical propellants had uniform structure.The density was0.81g/cm~3,with little change at these conditions.When the nitrocellulose/solvent ratio was fixed to 50: 3.0,the nitrocellulose spheres with a sphericity of 0.9were prepared.(2)The preparation and characterization of the double-based spherical propellants.The effects of the nitrocellulose/solvent ratios on the preparation of the double-based spherical propellants were studied by the micro-channel device.The surface morphology was characterized by SEM.The combustion performance of the double-based spherical propellants with the nitrocellulose/solvent ratio of 50: 3.5 was tested by the manometric bomb.Results showed that when the flow rate ratio of the water-oil phase was fixed to1000μL/min: 100μL/min and the nitrocellulose/solvent ratio of the dispersed phase was from 50: 2.5 to 50: 3.5,the stable oil droplets were prepared in the micro-channel.The particle size of the double-based spherical propellants was increased from 260μm to 300μm.The density was 0.92g/cm~3,with little change at these conditions.When the nitrocellulose/solvent ratio was fixed to 50: 3.5,the nitrocellulose spheres with a sphericity of 0.9 were prepared.And these nitrocellulose spheres had regular shape,good uniformity and good monodispersity.The experimental data showed that the combustion performance of spherical propellant is stable,and the combustion curve followed the law of spherical surface burning law.Thus the microfluidic technology provides a new method for manufacturing spherical propellants with uniform size.