双尺度小火焰模型预测混合层火焰中PAHs的生成

Dual-Scale Flamelet Model for Prediction of PAHs Formation in Mixing Layer Flame

本文验证了双尺度过程变量小火焰方法在层流混合层火焰中的适用性,该方法通过增加额外的过程变量CPAHs来提高传统过程变量小火焰方法对多环芳烃的预测能力.通过与直接数值模拟结果的先验和后验对比,证明了该方法的优越性.在后验验证中,由于对过程变量CPAHs源项的偏低预测继而导致了对多环芳烃组分峰值的预测偏低.通过分析直接数值模拟结果中的小火焰分支,推测过程变量CPAHs源项的偏低预测是小火焰的多维性造成的.

In this paper,the applicability of the dual-scale flamelet/progress variable approach was verified in a combusting laminar mixing layer.In this approach,an additional progress variable CPAHs was defined to improve the capability of the traditional flamelet/progress variable approach to predict the formation of polycyclic aromatic hydrocarbons(PAHs).This approach was validated by comparing with the detailed chemistry simulation.In the a posterior analysis,the mass factions of PAHs are under-predicted due to the under-prediction of the source term of CPAHs.By analyzing the flamelet in the results of detailed chemistry simulation,it is concluded that the under-prediction of the source term of CPAHs is caused by the multi-dimensional effect of flamelet.