Interaction Between a Coaxial Rotating Jet and a Reactive Core Flow

The compressible effects of conventional high-speed coaxial flows oppose the timescales required for mixing and subsequent deflagration. Despite the documented behavior of cold flows, there is a limited research focus on methods to improve combustion and mixing for reacting coaxial flows at high convective Mach numbers. In this paper, one such configuration is numerically modeled in three dimensions using adaptive mesh refinement and upwards of 200 million cells. The results are compared to a baseline case through one-dimensional averages of mixing and fuel consumption as well as a qualitative analysis of the flow field illustrating critical flow features. By imposing a time-dependent profile of pressure, temperature, and velocity in the secondary jet, the interface between the streams is destabilized more rapidly through asymmetric pressure gradients and shear stresses. The mixing layer consequently grows at a faster rate than in the baseline case, and a higher combustion efficiency is achieved within the same axial length. The present research demonstrates a successful approach for encouraging the onset of coaxial jet mixing and deflagration with potential applications in high-speed propulsion.