OPTIMUM DESIGN OF A TWO STEP PLANAR DIFFUSER: A HYBRID APPROACH

This study attempts to optimize a planar diffuser with two steps using a hybrid approach. It uses CFD softwares: Gambit for mesh generation, Fluent for carrying out hydrodynamic analysis, and employs a Genetic Algorithm (GA) for optimization. Here, the GA and CFD softwares combine each other seamlessly and exchange data among the commercial softwares (namely Gambit and Fluent) and optimization tool (that is, GA) in a fully automated manner without any human intervention. The hydrodynamic analysis is used to calculate pressure drop across the diffuser for a fully turbulent flow, while the GA determines its optimum design, which minimizes the same. The optimum dimensions of the diffuser wall have been determined for different values of Reynolds number and area ratios between the outlet and inlet of the diffuser. Finally, relationships of optimum geometrical dimensions with the Reynolds number and area ratio have been developed for the ready use of designers.