The paper describes a theoretical study on the influence of filtration of a mixture of gaseous products of pyrolysis and water vapor on the dynamic of ignition of coal-water fuel particles under conditions of high temperature heating. The developed mathematical model offers simulation of the process of ignition of coal-water fuel droplets under conditions close to the furnace space (characterized by intense radiation-convective heating) in typical boilers. Comparisons of experimental data (found previously) and simulation data on the ignition delay time (t_ign) demonstrate good compliance. Simulation results show that filtration of water vapor and volatiles is a significant factor (influence up to 40 %) affecting the characteristics and conditions of ignition of coal-water fuel droplets. The higher velocity of the vapor-gas mixture flow through the porous structure of the fuel particle results in a longer ignition delay. The effect of using the “simplified” model of filtration heat transfer on the prognostic estimates of coal-water fuel ignition is analyzed. It is demonstrated that using of rather simple models for filtration heat transfer does not bring any significant errors in calculating the ignition delay time.

中文翻译：

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过滤传热对煤水燃料颗粒着火参数和条件的影响

本文描述了在高温加热条件下，热解气态产物和水蒸气混合物的过滤对煤-水燃料颗粒着火动力学的影响的理论研究。所开发的数学模型提供了在典型锅炉中靠近炉膛空间（通过强烈的辐射-对流加热为特征）的条件下模拟水煤燃料液滴点火过程的模拟。点火延迟时间（t _ign）的实验数据（先前发现）与模拟数据的比较）表现出良好的依从性。模拟结果表明，水蒸气和挥发物的过滤是影响煤-水燃料液滴燃烧特性和条件的重要因素（影响高达40％）。蒸气-气体混合物流过燃料颗粒的多孔结构的较高速度导致较长的点火延迟。分析了使用“简化”的过滤传热模型对煤-水燃料着火的预后估计的影响。已经证明，使用相当简单的模型进行过滤传热不会在计算点火延迟时间时带来任何重大误差。