Large eddy simulation of hydrogen/air co-flow jet flame in the strut-based supersonic combustor

Abstract

The exploration of efficient combustion organization schemes is crucial as the expansion of scramjet to higher Mach number becomes a cutting-edge trend. This paper evaluates the combination of strut flameholder and co-flow jet injection scheme through Large Eddy Simulation. The study primarily investigates the combustion stabilization and flame blowout characteristics in various internal circular airflow rates and coaxial/eccentric design scenarios. The simulation results show that the partially premixed flame dominates the combustion process. The findings reveal that the proposed scheme can quickly increase the mixing and combustion efficiency to 20 % and 80 % within a 30 mm range post-strut. The mass flow rate setting of the inner air jet plays a pivotal role in determining the combustion process. Optimal combustion performance is attained with the use of an internal air jet with a diameter of 1 mm in the current configuration. Although an eccentric design is employed to enhance mixing, a 1.5 mm diameter air jet fails to maintain flame stabilization due to the influence of cold high-speed air on the velocity and energy of the recirculation zone. These conclusions provide valuable insights for the design of high-Mach scramjet.