基于ReaxFF MD的AlH3基高能推进剂与Al基推进剂热解氧化机理对比OA

To evaluate the potential of AlH3 as an alternative metallic fuel to Al and compare their pyrolysis oxidation behav-iors,Al-and AlH3-based propellant(ASP,AHSP)systems containing GAP/NG/BTTN/HMX/CL-20 were built.High tempera-ture pyrolysis oxidation of Al-based propellant(ASP)and AlH3-based propellant(AHSP)were simulated via ReaxFF molecular dynamics.The pyrolysis oxidation mechanisms were revealed by analyzing temperature,potential energy,RDFs,intermedi-ates,bonds,products and morphology of systems with different particle sizes and contents.The results show that AHSP pres-ents a more intense pyrolysis than that of ASP.Its unique characteristic of dehydrogenation and Al re-agglomeration pathway generates active Al intermediates and hydrogen in the initial reaction stage.Al atoms in AHSP migrate and agglomerate more significantly with faster core oxidation and larger cavities.AHSP shows a faster temperature increase than ASP during the early reaction phase,while there is 220K lower in the late stage.Key intermediates(OH,NO2,AlO)form faster,and the reaction proceeds earlier.AHSP yields more H2O and less CO2,N2.This work clarifies the mechanism difference caused by AlH3 repla-cing Al from the micro-scale view point,proving AHSP is superior to ASP in reaction rate,intermediates and gaseous products.