Nonlinear instabilities leading to rapid mixing and ocmbustion in ocnfined superfsonic double-shear-layer flow

摘要

Direct numerical simulaitos conducted in the present study show that a slow fuel gas stream issued between supersonic high-temprature air ttreams confined in a constant-area channel cna mix with air quickly to cause explosive combustion along the folliwng processes: (1) linear flaw instability excitation,(2) eddy fromaiton without shocks,fuel flow acceleration to supersonic speed and enhanced mixing with air,associated with fuel laeyr measndiering,(3) explosive combustion,and (4) thermally choked burnt gas flow.The unederlying physics of th supersonic instabiities involved are revealed by interpreting the simulation results in an attempt to find an effecitve imixing enhancement technque.