Abstract The effects of distance from the injector upstream to the cavity leading edge on combustion stabilization modes were investigated experimentally and numerically. High-speed flame luminosity and schlieren images were utilized to reveal the combustion characteristics. Under a Mach 2.52 supersonic inflow condition with a stagnation temperature of 1629 K, hydrogen was injected with injection distances of 30 mm, 100 mm and 160  mm at global equivalence ratios from 0.20 to 0.32. The flame in cavity stabilized mode is observed at a relatively low equivalence ratio. Increasing the global equivalence ratio, the combustion stabilization mode transfers to the jet-wake stabilized mode with injection distances of 100 mm and 160 mm. It is surprising that the mode transition is the easiest for the medium injection distance of 100 mm. Large eddy simulations were then performed to explain the easiest mode-transition. Mixing characteristics, jet-cavity interactions and the jet-wake features upstream of the cavity for three injection distances were analyzed. With the injection distance of 100 mm, the reflected shock wave impacts on the cavity shear layer, and the interactions of the shock wave structures and the cavity induce the beginning phase of the jet-wake stabilized flame and help the flame propagate upstream around the cavity. Relatively larger amount of the fuel, lower streamwise velocity and lower static pressure was also found in the jet wake upstream of the cavity, which further supports the flame to propagate upstream and stabilize in the jet wake.

    Highlights The cavity stabilized combustion mode and the jet-wake stabilized combustion mode are obtained. The medium injection distance induces the earliest mode-transition. The jet-cavity interactions with the medium injection distance induces the mode-transition. The jet-wake features upstream of the cavity further supports the flame to stabilize in the jet wake.


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    Title :

    Effects of fueling distance on combustion stabilization modes in a cavity-based scramjet combustor


    Contributors:
    Wang, Yanan (author) / Wang, Zhenguo (author) / Sun, Mingbo (author) / Wang, Hongbo (author) / Cai, Zun (author)

    Published in:

    Acta Astronautica ; 155 ; 23-32


    Publication date :

    2018-11-06


    Size :

    10 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English







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