Flowing residence characteristics in a dual-mode scramjet combustor equipped with strut flame holder

In this paper, the numerical and experimental investigations have been conducted to study the flowing residence characteristics in the supersonic combustor. A thin strut equipped in the center of the combustor was adopted as the flame holder. The airflow residence time was calculated by a new method, and results proved that the airflow residence time was longest in the center of the recirculation zone. Then, the interaction between the strut geometrical parameters and the airflow residence time was investigated. The results revealed that the thickness of the strut played a decisive role on the residence time and with the strut thickness increasing, the residence time became longer. The sweep angle and the length of the strut had few influences on the residence time. A series of experiments have been conducted at the flight condition of Ma = 6.5. Experimental results indicated that, with the help of the long residence time in the recirculation zone, an initial flame was formed in the recirculation zone at the tailing of the strut, and grew to form a steady flame in the center of the main flow. These results are valuable for the future optimization of the combustion stabilization in the supersonic combustor using strut as the flame holder. (C) 2020 Elsevier Masson SAS. All rights reserved.