Abstract
Extinction limits and flame bifurcation of lean premixed dimethyl ether-air flames were studied numerically using the counterflow flame with a reduced chemistry. A method based on the reaction front was presented to predict the Markstein length. The predicted positive Markstein length agreed well with the experimental data. The flow stretch significantly reduced the flame speed and narrowed the flammability limit of the stretched dimethyl ether-air flame. The combined effect of radiation and flow stretch resulted in a new flame bifurcation and multiple flame regimes. At an equivalence ratio slightly higher than the flammability limit of the planar flame, the distant flame regime appears at low stretch rates. With an increase of the equivalence ratio, in addition to the distant flame, a weak flame isola emerged at moderate stretch rates. With a further increase of the equivalence ratio, the distant flame and the weak flame branches merged together, resulting in the splitting of the weak flame branch into two weak flame branches, one at low stretch and the other at high stretch. Flame stability analysis demonstrated that the high stretch weak flame is also stable. A K-shaped flammability limit diagram showing various flame regimes and their extinction limits were obtained.
Original language | English (US) |
---|---|
Pages | 103 |
Number of pages | 1 |
State | Published - 2004 |
Event | 30th International Symposium on Combustion, Abstracts of Symposium Papers - Chicago, IL, United States Duration: Jul 25 2004 → Jul 30 2004 |
Other
Other | 30th International Symposium on Combustion, Abstracts of Symposium Papers |
---|---|
Country/Territory | United States |
City | Chicago, IL |
Period | 7/25/04 → 7/30/04 |
All Science Journal Classification (ASJC) codes
- General Engineering