Aerodynamic Design of Axe-symmetric Diffuser via Genetic Algorithm and Ball Spine Inverse Design

In this research, an aerodynamic design of axisymmetric diffuser is performed via linking a solver of boundary layer equations, Genetic Algorithm and Ball Spine inverse design algorithm (BSA). A numerical boundary layer code is incorporated to the genetic algorithm to reach an optimum pressure distribution on the diffuser wall in such a way that maximum pressure recovery is obtained without separation. To validate the developed boundary layer code, the calculated quantities are compared with Blasius and Howart’s analytical results. Then, the optimized pressure distribution is considered as the "target pressure distribution" for the inverse design algorithm to find out the relevant optimum geometry. For inverse design, Ball-Spine algorithm as the geometry modification algorithm is compined by the Fluent software as the flow solver. Implementation of this combination is completed through User Defined Function (UDF) feature of Fluent. Having examined the performance of the proposed inverse design method, quantitative effect of this method on the performance improvement of an axisymmetric diffuser is studied. The numerical results of the optimized diffuser shows that its pressure recovery coefficient has been increased considerably.