Numerical study of fuel mixing enhancement using an oblique shock/vortex interaction

The effects of swirl and jet-to-freestream pressure ratio on the mixing per formance of a swirling helium jet interacting with an oblique shock are inv estigated. The three-dimensional parabolized Navier-Stokes equations are so lved to simulate the parallel injection of a swirling helium jet at Mach 3 into a coflowing stream of air at Mach 4. The effects of swirl and jet-to-f reestream pressure ratios on the mixing performance are studied by consider ing various strengths for the swirling jet and various jet exit pressures, respectively. The mixing performance is based on several parameters that in clude the maximum helium mass fraction decay, the fraction of total helium mass flux present at various concentrations, and the total entropy rise. It is shown that the fraction of total helium mass Bur that is present at c(H e) less than or equal to 0.05 increases from 8 to 16% and that the point at which pure helium ceases to exist occurs farther upstream with the additio n of swirl. Furthermore, it is shown that the jet with the lower pressure a nd momentum provides better mixing performance than the higher pressure jet .