Effect of carbon dioxide concentration on the combustion characteristics of boron agglomerates in oxygen-containing atmospheres  

作　　者：Lian DUAN Zhixun XIA Yunchao FENG Binbin CHEN Jiarui ZHANG Likun MA 

机构地区：[1]College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China

出　　处：《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》2023年第11期949-959,共11页浙江大学学报（英文版）A辑（应用物理与工程）

基　　金：the National Natural Science Foundation of China(No.52006240);the Hunan Provincial Natural Science Foundation of China(Nos.2020JJ4665 and 2021JJ30775).

摘　　要：In ramjet combustion chambers,carbon dioxide(CO_(2))produced by the combustion of carbonaceous fuel enters the chamber together with boron agglomerates.In order to investigate the effect of CO_(2)concentration present in an oxygen-containing atmosphere on the combustion characteristics and oxidation mechanisms of boron agglomerates,we used a laser ignition system,an X-ray diffractometer(XRD),and a thermogravimetric-differential scanning calorimetry(TG-DSC)combined thermal analysis system.Single-particle boron was tested in the laser-ignition experiments as the control group.The ignition experiment results showed that with a fixed O2 concentration of 20%,when the particle temperature reaches the melting point of boron,increasing CO_(2)content causes the combustion process of boron agglomerates to transition from single-particle molten droplet combustion to porous-particle combustion.Furthermore,XRD analysis results indicated that the condensed-phase combustion products(CCPs)of boron particles in a mixed atmosphere of O2 and CO_(2)contained B4C,which is responsible for the porous structure of the particles.At temperatures below 1200℃,the addition of CO_(2)has no obvious promotion effect on boron exothermic reaction.However,in the laser-ignition experiment,when the oxygen concentration was fixed at 20%while the CO_(2)concentration increased from 0%to 80%,the maximum temperature of boron agglomerates rose from 2434 to 2573 K,the self-sustaining combustion time of single-particle boron decreased from 396 to 169 ms,and the self-sustaining combustion time of boron agglomerates decreased from 198 to 40 ms.This study conclusively showed that adding CO_(2)to an oxygen-containing atmosphere facilitates boron reaction and consumption pathways,which is beneficial to promoting exothermic reaction of boron agglomerates at relatively high temperatures.

关 键 词：Boron combustion Amorphous boron Boron-containing propellant Solid fuel ramjet 

分 类 号：V235.21[航空宇航科学与技术—航空宇航推进理论与工程]