Volume 2: Innovative Solutions for Energy Transitions: Part I

Large Eddy Simulation of N-Heptane Premixed Flame in Low Temperature Ignition Regime Shenghui Zhong , Ning Zhang , Mehdi Jangi , Fan Zhang* , Zhijun Peng, Xue-Song Ba

Abstract

This paper presents a Large Eddy Simulation (LES) study of the effect of low temperature chemistry on the structure and propagation of n-heptane/air turbulent premixed flame with transport Probability Density Function (t-PDF) model based on the Eulerian Stochastic Fields (ESF) method. The computation process is accelerated by conjugating ESF method with Chemistry Coordinate Mapping (CCM) approach. Initial n-heptane/air mixtures at an equivalence ratio of 0.6, a constant pressure of 1 bar and temperature of 600 K, 650 K and 700 K in a new RATS burner configuration are considered. The studied cases cover three regimes of combustion, a Chemical Frozen (CF) regime, a transition (TRA) regime and a Low Temperature Ignition (LTI) regime. The results showed that low temperature chemistry of n-heptane has a significant effect on the enhancement of turbulent flame speed. Also, CO emission widely exists in post flame zone in CF condition, whereas, it is quickly oxidized in reaction zone under LTI condition.

Keywords low temperature ignition, premixed flame propagation, Eulerian Stochastic Fields, LES method