水平碳粒床中阴燃过程的数值计算

Numerical simulation of smoldering process in horizontal carbon particles bed

利用控制容积法和ＰＩＳＯ算法对床上面具有受迫气流经过的水平碳粒填充床，从点火开始到稳态传播的整个阴燃过程进行了数值模拟．模型中包括三个异相反应和一个气相反应过程．计算表明：直径为１ｍｍ、空隙率为０．２６０、空气流速为０．０１ｍ／ｓ的水平床，当点火温度为９００Ｋ时，将不会产生明火．碳粒的堆积方式即填充床的空隙率对阴燃影响较大：空隙率越大，阴燃传播的峰值温度越高，传播速度越大．在一定范围内，床面上方的空气流速对阴燃传播影响不大．

The processes of smoldering propagation in a horizontal carbon particles bed, from the ignition until the steady state, have been modeled by numerical computation with an air stream over the bed. The PISO algorithm was used to solve the governing equations of the smoldering combustion. The model includes three heterogeneous reactions and a gas phase reaction. The following conclusions are drawn: When the ignition temperature was taken to be 900 K, flame does not occur in the horizontal bed provided that the carbon particle diameter is 1 mm, porosity is 0.260 and air velocity is 0.01m/s. The porosity is an important factor to smoldering combustion. The increasing of porosity will result in the raising of front temperature and the velocity of smoldering propagation. Within a limited range, the air velocity has little influence on the smoldering combustion.