Blowout characteristics of the partially premixed flame during the condition transition in a supersonic combustor. (October 2021)

• Record Type: Journal Article
• Authors: Jia, Dongpeng; Pan, Yu; Wang, Ning; Liu, Chaoyang; Yang, Kai
• Is Part Of: Acta astronautica. Volume 187(2021)
• Page Start: 315
• Page End: 324
• Publication Date: 2021-10
• Subjects: Condition transition -- Flame blowout -- Unsteady combustion -- Blowout limits; Astronautics -- Periodicals; Outer space -- Exploration -- Periodicals; Astronautics; Periodicals; 629.405
• DOI: 10.1016/j.actaastro.2021.06.048
• Languages: English
• ISSNs: 0094-5765

Abstract

Abstract: The blowout characteristics of partially premixed flame during the condition transition in a cavity-stabilized scramjet combustor are investigated by the experimental method. More attention is placed on the unsteady evolution of the turbulent jet flame, as well as its dynamic response with the initial reactive flow states. The Mach number of flow at the entrance of the combustor is 2.52, the total pressure and the stagnation temperature of which are 1.6 MPa and 1486 K. The cavity-stabilized jet flame is blown out once the injection pressure drop reaches a critical value. During the flame blowout process, the most strongly reactive region gradually transits from vicinity of the cavity shear layer to downstream. Accompanied the sharply decrease of combustion intensity, the light intensity drops rapidly until the flame is completely extinguished. The experimental results indicate that the dynamic process of flame blowout depends on the initial reactive flowfields. The jet flame lasts longer and more intermediate products with high temperature reside within the combustor, which is beneficial to ignite the combustible fuel mixed in the air. As the increase of initial combustion intensity, the flame can be maintained in the combustor at a lower limit of global equivalence ratio after the condition transition. The results on the flame blowout limits are of great significance for the design of the condition transition in a scramjet. Highlights: The flame blowout characteristics during the condition transition are experimentally investigated. The dynamic blowout process of the flame with a low equivalence ratio are analyzed in detail. More intermediate products with high temperature exist within the combustor with a stronger initial combustion intensity. The lean critical blowout limit is closely related to the initial reactive flowfields.