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针对相对静止气氛下单颗粒硼的着火过程展开了系统研究,考虑硼颗粒周围径向气相流动以及硼颗粒与周围环境间的传热和传质过程,建立了一维硼颗粒着火模型。分析了硼颗粒在实现着火和未能实现着火两种典型情形下的颗粒相、气相组分参数以及颗粒外表面上Stefan流的变化规律,并对其成因展开了分析。研究表明,在实现着火和未能实现着火两种典型情形下,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;考虑颗粒外表面处气相Stefan流作用后,硼颗粒的着火延迟时间减少,且压力越大,影响越大。
Aiming at the ignition process of single particle boron under relative still atmosphere, a one-dimensional boron particle ignition model was established considering the radial gas flow around boron particles and the heat and mass transfer between boron particles and the surrounding environment. The particle phase, gas phase composition parameters and the Stefan flow on the outer surface of the particles were analyzed under two typical conditions of ignition and failure to achieve ignition. The causes of the formation were analyzed. The results show that the Stefan flow on the outer surface of boron particles undergoes the first flow from the surrounding space to the particle surface and then the flow from the particle surface to the surrounding space under both typical conditions of ignition and failure to achieve ignition. Considering the outer surface of the particle After the gas-phase Stefan flow, the ignition delay of boron particles decreases, and the greater the pressure, the greater the impact.