The Research On Constant-volume Combustion Performance Of Mixed Charge And Coated Propellants Charge

In order to study combustion performance of mixed charge and coated propellants charge with constant volume,different types of granular propellants and stick propellants were prepared,which were coated by coating polymeric flame materials with TiO₂.The closed-bomb tests and semi-closed vessel tests of coated propellants,slotted stick propellants and deterrent coated granular propellants,granular propellants and coated granular propellants,slotted stick propellants and deterrent coated slotted stick propellants were carried out,and combustion performance of propellants charge in different coated condition,loading densities,types of propellants and mixed mass ratio with constant volume was investigated.The influence of composite of propellants on combustion by L-B curves fit was studied.The results show that deterrent coated propellant increased burning progressivity.It was also found that as TiO₂ content and the thickness of layer increase,combustion progressivity gets better.In this experiment,while coated layer weight fraction is 20%and TiO₂ in the coated layer is 30%,combustion progressivity of deterrent coated propellants is better.The influence of coating process condition on burning progressivity and low temperature sensitivity is apparent.Different coated propellants with different burning progressivity and low temperature sensitivity were prepared by different process condition.The incision intervals of slotted stick propellants affected the combustion law,the initial erosive burning increased when the incision intervals increased.The gradual combustion decrease when the incision intervals is too small.Loading density impacted the combustion of mixed charge,the higher loading density can increase burning progressivity and decrease erosive combustion.In this experiment,the suitable mass mixed ratio of slotted stick propellant and deterrent coated granular propellant is 7:3 when loading density is 0.32g·cm^-3,which can lead to a good combustion progressivity.Combustion mechanism of slotted stick propellant and other coated propellant was analyzed.It was also found that slotted stick propellants and other coated propellants interact seriously in the early stages of combustion.The slotted stick propellants improved the effect of ignition.However,as the combustion progresses,the interaction between them gradually weakens.