Energy & Fuels, Vol.28, No.3, 2189-2198, 2014
Experimental and Modeling Study on Ignition Delay Times of Dimethyl Ether/n-Butane Blends at a Pressure of 2.0 MPa
In this study, the ignition delay times of dimethyl ether (DME)/n-C4H10 fuel blends, neat DME, and neat n-C4H10 diluted with argon were measured behind reflected shock waves. The experiments were performed in the temperature range of 1100-1600 K, at a pressure of 2.0 MPa, and equivalence ratios from 0.5 to 2.0. A latest kinetic mechanism NUIG Aramco Mech 1.3 was validated against the measured ignition data and used to conduct the chemical kinetic analysis. Results showed that different equivalence ratio-dependent behaviors were exhibited at different temperature regimes for DME, n-C4H10, and their blend. The ignition delay time of neat n-C4H10 was increased with an increase in the equivalence ratio. A strong inhibiting trend was exhibited at high temperatures. For the neat DME, however, an opposite influencing tendency from the equivalence ratio was presented in comparison to that on n-C4H10. Ignition promotion becomes significant at relatively low temperatures. A 50% DME/50% n-C4H10 blend show a combined behavior of both n-butane and DME. Fuel reaction flux analysis, sensitive analysis, and mole fraction analysis were conducted for the understanding of the interaction between the ignition chemistries of DME and n-C4H10 at a pressure of 2.0 MPa.