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针对冲压发动机燃烧室内强迫对流下的硼颗粒燃烧特性展开了系统研究,考虑气相流动、扩散和表面单步有限化学反应动力作用,建立了强迫对流下硼颗粒燃烧过程的物理和数学模型;采用有限体积法求解含多组分反应流的二维轴对称Navier-Stokes方程,并验证了数值仿真方法的正确性。首先通过数值仿真研究了来流速度、颗粒半径、环境中氧气质量分数和环境压力等因素对硼颗粒燃烧特性的影响,并对其成因展开了详细分析。研究表明,在强迫对流作用下,硼颗粒总的燃烧质量流率和质量流率通量均随来流速度、颗粒半径、环境中氧气质量分数和环境压力的增加而增大。通过深入分析发现,强迫对流下硼颗粒的燃烧质量流率通量随着来流雷诺数的增加而增大。然后基于大量数值仿真结果,对相对静止气氛下的硼颗粒质量流率通量进行了修正,用于描述强迫对流下的硼颗粒燃烧特性。
A systematic study on the combustion characteristics of boron particles under forced convection in a ramjet engine was carried out. The physical and mathematical models of the combustion process of boron particles under forced convection were established considering the gas flow, diffusion and single-step kinetic reaction. Dimensional method to solve the two-dimensional axisymmetric Navier-Stokes equation with multi-component reaction flow, and verify the correctness of the numerical simulation method. Firstly, the influence of flow velocity, particle radius, oxygen mass fraction in the environment and ambient pressure on the combustion characteristics of boron particles was studied by numerical simulation. The causes of formation were analyzed in detail. The results show that under forced convection, the total combustion mass flow rate and mass flow rate flux of boron particles both increase with the increase of flow velocity, particle radius, oxygen content in the environment and ambient pressure. Through in-depth analysis, it is found that the mass flow rate flux of boron particles under forced convection increases with the increase of Reynolds number. Based on a large number of numerical simulations, the mass flow rate of boron particles in a relatively quiescent atmosphere was modified to describe the combustion behavior of boron particles under forced convection.