The effect of swirl intensity on the probability of successful ignition and kernel propagation in the Amirkabir double swirl burner.

In this article, the influences of swirl intensity on the mixing pattern, successful ignition probability, and flame propagation manner in a non-premixed gas burner with natural gas fuel have been examined by using numerical simulation and high-speed digital imaging. The ignition success probability maps were scrutinized under changing spark location in axial and radial directions. The flow field and mixing pattern were further inspected with the aid of numerical simulation. High-speed digital imaging was employed to study the initial flame kernel propagation. The ignition success probability diagrams defined three areas. The first, dubbed the ineffective zone, holds less than a 20% ignition success chance. The second, known as the transitional zone, has an ignition success probability between 20% and 80%. Ignition success here significantly depends on the spark location. The third area—the high-probability zone—has over an 80% ignition success chance. Findings from the study demonstrate an increased swirl number promotes a higher mixing rate, but it doesn't enhance the distribution of successful ignition probability. Higher swirl numbers actually reduce the high-probability zone, whereas lower swirl numbers allow a broader distribution in the burner outlet and better ignition characteristics.