Wind & Renewable Energy

Biography

Biography: Tomasz Szafranski

Abstract

This paper presents development of a light shell diffuser with a frame intended for a small wind turbine (rated power of 3kW). The concept was created as an attempt to reduce the mass of the diffuser made of glass fibre composites which are the most commonly used materials for such applications nowadays. The geometrical shape of the diffuser, developed at Technical University of Lodz, was based on computed fluid dynamics (CFD) simulations considering turbine efficiency optimization for low wind speed conditions. The authors focused on developing an overall structural design, as well as detailed technical solutions (stiffener struts, connections, material forming issues). Subsequently, static structural finite element analysis was performed in order to assess stiffness and stress distribution. In this case, load conditions include pressure field from the CFD analysis and gravitational forces. The obtained results lead to a conclusion that the designed aluminium shell frame diffuser may be an alternative option for a composite diffuser. Moreover, the developed structure is characterised by lower mass and comparable stiffness to its composite counterpart. It is worth mentioning that, lighter diffusers allow a use of lighter supporting structures, such as towers or guyed masts. This fact may contribute to reducing the overall costs of future small wind turbines and could potentially be very beneficial for the market of privately owned small wind turbines. The study was supported by the National Centre for Research and Development in Poland within project “STOW” - Small Wind Turbine Optimized for Wind Low Speed Conditions. This support is gratefully acknowledged.