The Effects of the Aspect Ratio of the Finite Length Slit on the Mixing in a Three Dimensional Supersonic Flow

The supersonic flow fields and mixing fields with a perpendicular hydrogen injection from a finite length slit are investigated. The finite length slit means the slit with two ends. The numerical simulations are performed by using three dimensional full Navier-Stokes equations and two conservation equations of the chemical species. The parameter in the calculations is the aspect ratio of the finite length slit. The aspect ratio means the ratio of the lateral length to the streamwise width of the finite length slit. The aspect ratio is changed to keep the area of the injection slit constant. The results show that the total pressure loss is maximum at the aspect ratio of one because the injected hydrogen penetrates deep into the main flow, and the mixing efficiency has the two minima in each region where the aspect ratio is less than one and more than one. It is found that the contact (or mixing) area of the main flow air and the injected hydrogen is important to the mixing in the supersonic flow.