Numerical and Experimental Studies of NO Formation Mechanisms under Methane Moderate or Intense Low-Oxygen Dilution (MILD) Combustion without Heated Air

Abstract

moderate or intense low-oxygen dilution (MILD) combustion a newly developing and innovative combustion technology. A MILD combustion without preheated air was achieved with inner flow recirculation and simulated by a computational fluid dynamics (CFD) model with GRI-Mech 3.0. Comparisons between the experimental and predicted results, including temperature and O2, CO, and NO concentration fields, demonstrate that the model closely predicted MILD combustion without preheated air and is suitable for studying the NO formation mechanism under these conditions. According to the distribution of NO and NO2, there are three zones in the furnace: a central zone (I), a transition zone (II), and a recirculation zone (III). The NO concentration is lowest in the central zone, highest in the recirculation zone, and intermediate in the transition zone. The NO2 concentration is high in regions where the NO concentration is low and low in regions where the NO concentration is high. The NO formation mechanism is that NH3, ...