Investigation of flow and power parameters of a vertical axis water turbine for river application

In this experimental study, it has been designed and calculated of (3 bladed) Darrieus wind turbine (with 3 blades) which has the power of 5 kW in the vertical axis for free stream velocity between 2.2-2.5 m/s. Rigidity ratio (σ) and attack angle (α) are defined as 1.1 and -2 respectively. Here, the sizes of TS3 that is an irrigation canal in Adana are taken as references or (used) for the optimum values of chord length (CL), radius (R), and height of the turbine blades (H). A prototype design has been performed by using a 3D solid modelling software with respect to optimum values obtained from the canal in Adana. A ¼ scale turbine has been modelled and produced to analyse of the flow of the prototype experimentally. Changes in the flow around the blades and the turbine have been investigated experimentally by using PIV method for 4 different azimuth angles θ=270°, θ=240°, θ=210°, θ=180° and 3 different Re numbers 9000, 14000, and 20000. Here, the Reynolds numbers are obtained using the chord length (ReCL). As a result of the flow analysis, time-averaged velocity vectors averaged flow lines <> mean vortex fields <ω> were obtained and interpreted. It was observed that change in the shapes and the regions where time-averaged velocity vectors , averaged flow lines <> average vortex fields <ω> occur. Furthermore, formations of the vortex focal (F) and stagnation (S) areas were observed. The increase in the Reynolds number causes a change in the formation coordinates of F and S points as well as the change in the flow structures