Flow Fields and Extinction of Stretched Cylindrical PremixedFlames

Abstract

The flow fields were measured for the stretched cylindrical premixed flame and the counterflowtwin flames with stoichiometric methane-air mixtures using LOV. A quantitative comparison of the flowstructure was made based on the actual velocity gradients and flame stretch rates. The similarity betweenthe flow structures for both flame types was clarified over a wide range of velocity gradients. The extinctioncharacteristics were compared with each other and it was shown that the cylindrical flame was extinguishedat a lower velocity gradient and a lower stretch rate than the twin flames. The flame diameter of thecylindrical flame at the state of flame extinction was larger than the flame distance for the twin flames. Themechanism behind these characteristics was discussed from the view point of investigating the effects ofhigh curvature on the extinction for highly stretched flames.

Keywords:

• Flow Field

Keywords:

• Extinction

Keywords:

• Flame Stretch

Keywords:

• flame Curvature

Keywords:

• counter flow