Numerical optimization of air breathing radial outflow turbines

Small air driven alternators serve as a practical solution to be a power source for miniature electronic equipment. An air-breathing radial outflow turbine can be easily manufactured and implemented to a variety of terrestrial and aerial vehicles for auxiliary power generation. The flow characteristics of such turbines need to be understood in order to maximize the power output with a compact design. The present study aims to document a numerical optimization strategy to improve the performance characteristics of small radial outflow turbines. The geometry is parametrized such a way that it allows automatized geometry and grid generation depending on the decided geometrical variables. The optimization was then performed with in house tool of VKI. The optimum design provided 33% higher power output than the initial design at the same rotational speed and mass flow rate. The final turbine geometry is without the hub gap and has smaller and higher blades.