Effects of flame stretch and flame curvature on the extinction of turbulent premixed flames in a stagnation point flow have been studied experimentally. A lean propane/air mixture was used. Bulk stretch rate was varied from 15 s-1 to 60 s-1, while the turbulence intensity of velocity fluctuation in the approach flow was varied up to 0.6 m/s. Near the extinction limits, the local stretch rate was estimated by measuring the mean centerline velocity with LDV and the local flame curvature was measured using a laser tomographic method. The local stretch rate due to flow divergence decreases, while the stretch rate due to the local flame curvature increases with increase in the turbulence intensity. As a result, it is proposed that the sum of those two stretch rates plays a key role in flame extinction.
|JSME International Journal, Series 2: Fluids Engineering, Heat Transfer, Power, Combustion, Thermophysical Properties
|Published - 1992 5月 1
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