Computational Investigation of Jet Mixing Enhancement by C-D Nozzle using Triangular Tabs

This computational study deals with the flow development, jet characteristic decay and mixing enhancement of jet from a C-D nozzle with triangular tab and without tab at the nozzle outlet with design Mach number of 1.8. The triangular tabs are placed opposed to each other at the nozzle outlet. The effect of the tabs on mixing and jet decay characteristics has been investigated. The C-D nozzle and the triangular tab are designed in design modeler and the simulation is done using ANSYS Fluent. The analysis is also done for under expanded and overexpanded conditions in both the cases with nozzle pressure ratio (NPR) 4 and 7.2. The comparison is made between the jets from nozzle without tab and nozzle with triangular tab using Mach number and pressure contour plots. A series of shock cells is observed clearly in two cases. The shock cell length and shock strength decrease for the jet at the presence of triangular tab. This results in a quicker decay of the jet in nozzle with tab case. The comparison between the both cases shows that the C-D nozzle with tab at the nozzle exit is recognized to be the superior mixing promoter compared to nozzle without tab.