Addition of nitramine particles (RDX) to composite solid propellants are promoted in advanced propulsion systems for better performances, high energy, high specific impulse, and environmentally benign combustion products. This study is performed for understanding the combustion mechanism of RDX based matrices and sandwich propellants. Four types of fine AP/Al/binder matrix mixtures are considered, two samples contain 5% and 20% RDX while another two mixtures are without RDX, for comparison. Burning rate experiments are carried out on sandwich propellants and matrices in the pressure range of 2–10 MPa. The condensed phase behaviour of RDX decomposition and RDX melt flow, their influence on the matrix flame and interaction with leading edge flames (LEFs) located over lamina interfaces of sandwich propellants are assessed from quenched surface profiles and SEM micrographs. The effect of middle lamina thickness and pressure on burning rates of sandwich propellants are investigated. It is noticed that different levels of addition of RDX to matrix induces either an increase or decrease in burning rates depending upon the composition and fine AP/binder ratio. The binder melt flow effect is reduced in RDX containing matrix lamina due to presence of near-surface premixed flame. The effect of middle lamina thickness on burning rates of RDX containing sandwich propellants is significant. The overall burning rates of RDX sandwich propellants are relatively high when compared to their corresponding non-RDX counterparts. This is due to the existence of RDX assisted matrix flame that re-establishes the interaction between the LEFs anchored over lamina interfaces. Such matrix flames that are located over the regions of matrix in inter-particle spaces of the propellant microstructure would have a positive effect on the LEFs and outer diffusion flames over coarse AP particles.

在先进的推进系统中，向复合固体推进剂中添加了硝胺颗粒（RDX），以获得更好的性能，高能量，高比冲和对环境无害的燃烧产物。进行这项研究是为了了解基于RDX的基质和夹心推进剂的燃烧机理。为了进行比较，考虑了四种类型的精细AP / Al /粘合剂基体混合物，两个样品含有5％和20％的RDX，而另外两种混合物不含RDX。在2-10 MPa的压力范围内，对夹心推进剂和基质进行了燃烧速率实验。RDX分解和RDX熔体流动的冷凝相行为，通过淬火的表面轮廓和SEM显微照片评估了它们对基体火焰的影响以及与夹层推进剂层界面上的前缘火焰（LEF）的相互作用。研究了中间层厚度和压力对夹心推进剂燃烧速率的影响。注意到，根据组成和精细的AP /粘合剂比，向基质中添加不同水平的RDX会引起燃烧速率的增加或降低。由于存在近表面的预混火焰，在包含RDX的基质薄层中降低了粘合剂的熔体流动效应。中间层厚度对含有夹心推进剂的RDX燃烧速率的影响是显着的。与它们对应的非RDX对应物相比，RDX夹心推进剂的总燃烧率相对较高。这是由于RDX辅助基质火焰的存在，它重新建立了锚固在薄片界面上的LEF之间的相互作用。位于推进剂微结构的颗粒间空间中的基质区域上方的此类基质火焰将对LEF和粗AP颗粒上的外部扩散火焰产生积极影响。