EXPERIMENTAL AND MODELING STUDY OF PREMIXED ATMOSPHERIC-PRESSURE DIMETHYL ETHER-AIR FLAMES E. W. Kaiser,* T. J. Wallington,* and M. D. Hurley Chemistry Department Ford Motor Company P. O. Box 2053, Mail Drop 3083/SRL Dearborn, MI 48121-2053 J. Platz The National Environmental Institute Frederiksborgvej 399 DK-4000, Roskilde, Denmark H. J. Curran,* ,a W. J. Pitz, and C. K. Westbrook Lawrence Livermore National Laboratory Livermore, CA 94550 ABSTRACT Chemical species profiles have been measured at atmospheric pressure for two dimethyl ether (DME)-air flat flames having fuel-air equivalence ratios of 0.67 and 1.49. The samples, obtained with an uncooled quartz probe, were analyzed by either gas chromatography or Fourier transform infrared (FTIR) spectroscopy for CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 , C 3 H 8 , DME, CO, CO 2 , O 2 , CH 2 O, and formic acid. A pneumatic probe calibrated at a reference position in the burned gas by a radiation-corrected thermocouple provided temperature profiles for each flame. Species profiles for two methane-air flames with equivalence ratios and cold gas flow velocities similar to those of the DME flames were also obtained for comparison to the DME results. Mole fractions of C 2 product species were similar in DME and methane flames of similar equivalence ratio. However, the CH 2 O mole fractions were 5-10 times larger in the DME flames. These experimental profiles are compared to profiles generated in a computer modeling study using the best available DME-air chemical kinetic mechanism. The Appendix presents photographs of DME, methane, and ethane diffusion flames. These results show that, while DME produces soot, its yellow flame luminosity is much smaller than that of an ethane flame at the same fuel volume flow rate, consistent with the low soot emission rate observed when DME is used as a diesel fuel. *Authors to whom correspondence should be addressed a Current address: Chemistry Dept., Galway-Mayo Institute of Technology, Dublin Road, Galway, Ireland