Experimental and numerical study on the ignition delay times of dimethyl ether/propane mixtures in O2/CO2 atmospheres

Abstract

This work measured the ignition delay times (IDTs) of dimethyl ether (DME)/propane mixtures in O2/CO2 atmosphere in a shock tube at an equivalence ratio of 0.5, a temperature range of 1157–1380 K, pressures of 2 and 10 atm, and a DME blending ratio range of 0–100%. A detailed kinetic model referred to as the DME-C3H8 model was constructed based on the OXYMECH 2.0 model and the DME sub-mechanism of Aramco 3.0. The DME-C3H8, Aramco 3.0, NUIG 1.0, and Dames models were evaluated through the IDTs obtained in the present study, and from literature in O2/N2 and O2/Ar atmosphere. The impact of the DME blending ratio was investigated using the DME-C3H8 model, and results show that the IDTs in O2/CO2 atmosphere at pressures of 2 and 10 atm decrease linearly with increased DME blending ratio; there exists a clear synergy effect between DME and propane in the O2/N2 atmosphere at the pressure of 2 atm, which is significantly weakened at the pressure of 10 atm. The impact of CO2 and pressure on the ignition were discussed in detail.