Experimental and numerical study on NOx and CO emission characteristics of dimethyl ether/air jet diffusion flame

Abstract

Abstract Dimethyl ether (DME) is one of the most promising alternative fuels emerging in the past few decades. At present, DME is mainly applied to the compression ignition (CI) engines, and numerous studies showed its superior performances in CI engines versus the traditional fuels. More recently, DME was also introduced into the field of industrial boiler to solve the pollution problem raised by coal usage. But the emission behavior of DME in this type of combustion system was not studied as thoroughly. In this paper, experiments and simulations are conducted to study the NOx and CO emission characteristics of the DME/air jet diffusion flame, which may be valuable for design and operation of the DME-fueled industrial boilers. During the measurements, a series of fuel jet velocities (uf) and air co-flow velocities (uco) were designed for the experiments to investigate their effects on NOx and CO emission indices systematically. Additionally, the CFD–CRN method was also employed to analyze NOx formation characteristics in different regions of the flame. The conversion relationship between the nitrogenous species (including NO, NO2, HCN, etc.), NOx formation and consumption pathways, and NOx and CO emission indices of the DME/air jet diffusion flame were analyzed by reaction rate and sensitivity analyses.