The hysteresis phenomenon in flame lift-off on a bluff-body burner under airflow dominant conditions

We investigated the behavior of the lifted flame on a bluff-body burner under the airflow dominant condition by the higher annular airflow velocity and the lower central fuel jet one and found the appearance of the hysteresis phenomenon in lift-off height of the flame that depends on the history of the fuel jet velocity. The hysteresis behavior is entirely different from the case of the fuel flow dominant condition by the higher central fuel jet velocity and lower annular airflow one. The observation by shadowgraph revealed that the occurrence of the phenomenon has a relation to the interaction between the fuel jet and the recirculation airflow region on the burner.