Multiobjective Design Optimization of a Mach 6 Hypersonic Nozzle of a Shock Tunnel

In this paper, a systematic approach is considered to Design an optimal hypersonic Nozzle of a shock tunnel. After assigning the requirements and accomplishment of conceptual and preliminary design phases, a modern optimization strategy based on genetic algorithm and a CFD solver has been used to fine tune the nozzle convergent divergent contour. In this way, parameterization of the overall nozzle contour was done with a few control points and a Bezier curve. This arrangement showed a good flexibility to generate appropriate curves for nozzle shape. Design objectives were evaluated with a N-S viscous solver with a two equation turbulence model. Three objective functions were scalerized in a term with summation of weighted parameters: minimum total pressure loss, Mach number uniform distribution along test section and minimum axial flow deviation. A number of geometrical and physical constraints such as nozzle length, throat area, inlet and outlet diameters and inlet boundary conditions were also considered and finally, an optimized nozzle contour showed a significant improvement of about 3% in quality of the Mach 6 flow in the test section.