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针对含硼推进剂固体火箭冲压发动机内单颗粒硼的着火过程展开了系统研究.考虑硼颗粒周围气相流动以及硼颗粒与周围环境间的传热传质过程,建立了考虑Stefan流作用的一维硼颗粒着火模型,研究了硼颗粒实现着火和未能实现着火两种典型情形下硼颗粒及周围气相的参数变化规律,对两种情形下Stefan流的变化规律及其成因展开了详细分析.研究表明,在硼颗粒实现着火的过程中,液态B2O3的蒸发及硼的氧化均能在硼颗粒的反应自加热作用下急剧加速,硼颗粒表面附近的氧气和气相B2O3分布变化剧烈;在未能实现着火的过程中,液态B2O3的蒸发和氧气消耗的质量流率相对较小,并逐渐趋于稳定,硼颗粒表面附近的氧气和气相B2O3分布相对变化很小.在两种典型情形下,硼颗粒外表面的Stefan流都会经历先由周围空间流向颗粒表面,而后变为由颗粒表面流向周围空间的过程.
Aiming at the ignition process of single particle boron in solid rocket ramjet with boron propellant, a systematic study was made on the ignition process of single particle boron in solid rocket ramjet engine.Based on the gas-phase flow around boron particle and the heat and mass transfer process between boron particle and the surrounding environment, Boron particle ignition model, the boron particles and the failure to achieve the ignition of two typical cases of boron particles and the surrounding gas phase parameters of the law, the two cases of Stefan flow changes and their causes were analyzed in detail. It is indicated that the evaporation of B2O3 and the oxidation of boron both accelerate rapidly in the reaction of boron particles under the action of heating and the distribution of B2O3 in the oxygen and gas phase near the surface of boron particles changes sharply during the ignition process of boron particles. In the process of ignition, the mass flow rate of liquid B2O3 evaporation and oxygen consumption is relatively small, and tends to be stable, the relative changes of B2O3 distribution in the oxygen and gas phase near the surface of the boron particles are relatively small.In two typical cases, boron particles The Stefan stream on the outer surface undergoes the first flow from the surrounding space to the particle surface and then to the flow from the particle surface to the surrounding space.