惰性颗粒抑制CH_4/O_2/N_2爆炸过程的二维数值模拟与实验验证

Two-Dimensional Numerical Simulation and Experimental Validation of CH_4/O_2/N_2 Explosion Suppression by Inert Particles

使用带基元化学反应的两相Eu ler方程,对惰性颗粒抑制高温火团诱导的CH4/O2/N2爆炸过程进行了二维数值模拟.其中,采用全耦合二阶精度的TVD格式求解气相方程,采用M acCorm ack格式求解惰性颗粒相方程,同时用分步方法处理方程组的耦合刚性,用Gear隐式方法处理化学反应刚性.计算并讨论了不同颗粒相浓度条件下,气相压力场、气相密度和颗粒相浓度的分布、爆炸衰减的气相结构以及两相间的能量传递.结果表明,惰性颗粒相的堆积可阻碍气相爆炸波的传播,使其衰减为引导激波,引导激波继续向颗粒相传递能量,而进一步衰减最终使得爆炸波被抑制.随着颗粒相浓度的增大,爆炸波的抑制更明显.计算结果与大型水平管的实验结果进行了比较,定性证明了计算的合理性.

A two-dimensional CH4/O2/N2 explosion suppression process by inert particles was simulated numberically by using two-phase Euler equations coupled with element chemical reactions. The gas phase equations were solved with the second order global coupled TVD scheme;the solid phase equations with inert particles were solved with the MacCormack scheme;a splitting method was adopted to treat the stiffness of coupled equations;the implicit Gear algorithm was used to treat the chemical stiffness. The present paper computed and discussed the two-dimensional gas phase pressure field, the distributions of gas and particle phase cloud density, the structures of gaseous species and temperature, and the energy transfer between the two phases under the different inert particle cloud densities. The results show that due to the accumulation of inert particles the explosion wave is dragged, and become an induced shock wave. The induced shock wave is further attenuated and suppressed as the energy transfers from gas-phase to particle-phase. When the particle cloud density is increased, the explosion suppression is more obvious. A qualitative agreement is obtained by comparing the computed results with large-scale duct experimental results.