Laminar Flame Characteristics and Kinetic Modeling Study of Ethyl Tertiary Butyl Ether Compared with Methyl Tertiary Butyl Ether, Ethanol, iso-Octane, and Gasoline

Laminar flame speeds of ethyl tertiary butyl ether (ETBE) were measured in a constant volume bomb at different initial temperatures (298 K, 373 K, 453 K) and pressures (1 atm, 3 atm, 5 atm). The laminar flame experiments were also conducted for methyl tertiary butyl ether (MTBE), ethanol, iso-octane, and gasoline for the comparison of laminar flame speeds and Markstein lengths. Experimental results show that laminar flame speeds peak at the equivalence ratio of 1.1 for all tested fuels. Ethanol has the fastest laminar flame speed and the other fuels have similar flame speeds, indicating replacing MTBE with ETBE in gasoline will not influence the laminar flame speed of present gasoline. The CRECK and Curran mechanisms were validated by experimental results of ETBE and neither could predict laminar flame speeds well. Curran mechanism was optimized by updating the underlying mechanism, and the Modified Curran mechanism has better prediction performance on the laminar flame speed. Sensitivity analyses were also provided to interpret the differences of laminar flame speeds and the major reason for better prediction performance for Modified Curran mechanism. The result of Markstein length shows that gasoline has the smallest Markstein lengths and its flame front is the most unstable. The Markstein lengths of ETBE and iso-octane differ little and are the largest under ϕ < 1.2. Ethanol has the largest Markstein lengths under ϕ > 1.2.