Numerical optimization of air breathing radial outflow turbines

Abstract

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. KEYWORDS optimization, radially outflow turbine, CFD NOMENCLATUREh average cell size m mass flow rate r radius T torque U peripheral velocity V absolute velocity, volume of a computational element W relative velocity DOE pitch OPT optimization POP population PS pressure side SS suction side β pitch ω rotational speed

Additively Manufactured Parts Made of a Polymer Material Used for the Experimental Verification of a Component of a High-Speed Machine with an Optimised Geometry—Preliminary Research

“…The method proposed by the authors could be used to produce prototypical parts that would be ready for testing. A result of such an optimisation can be a simple geometry like in [ 45 , 46 ], where the geometry was optimised to improve the flow performance and thus the efficiency of the machine (a, b). In such cases, optimisations can be carried out simultaneously in several variants, taking into account economic aspects such as a cheaper and faster manufacturing process.…”

“… Examples of geometry optimisations carried out on fluid-flow machines: ( a ) optimisation of the geometry of the blades of a gas microturbine [ 45 ]; ( b ) optimisation of the rotor of an air-breathing radial outflow turbine [ 46 ]; ( c ) optimisation of the guide vanes of an ORC microturbine [ 47 ]; ( d ) optimisation of the disc of a radial-axial turbine [ 37 ]. …”