Numerical study of flow stream in mini wawt with relative rotating blades | CD-adapco

Numerical study of flow stream in mini wawt with relative rotating blades

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Vertical-axis wind turbines (VAWTs) have been shown to be useful machines to extract energy from the wind. It allows a large scale of power energy which can be extracted from small scale applications through to large scale electricity production. The present study concerns small scale applications. Some inventors discovered this kind of turbine in the same time on different places (in France, in Australia…) these last ten years. This paper concerns an industrial one used to light publicity panel but it can be also used to light small areas like parking, roads or for water pumping for example. The vertical axis wind turbine studied in this paper combine two rotations: one rotating movement of each blade around its own axis and one rotating movement around turbine’s axis. One of the main problems of such geometry is to simulate the two combined movements. Due to this combination of movements, flow around this turbine is unsteady and needs to be modeled by unsteady calculation. The present work is an extended study of others’ started in 2009. In the previous studies the influences of two sketches of blades, of Reynolds number, of initial blade stagger angles and of blade speed ratios have been studied. The following conclusions have been drawn: - The performance of this kind of turbine was very good and better than those of classical VAWTs for some specific blade stagger. - Each blade behavior seems to have less influence on flow stream around next blade and on power performance. - The maximum mean numerical coefficient at a blade speed ratio equal to 0.4 was about 38%. - A low influence of Reynolds number for a wide range of wind speeds - A significant influence of sketch of blades depending on other parameters like blade speed ratios and initial blade stagger angles. - A significant influence of blade speed ratios - A significant influence of initial blade stagger angle A wide range of results have been obtained and still needs more analyses to understand all what happens in this VAWT. The aim of this paper is to analyze numerical results of unsteady calculations that have been performed for one wind velocity and different blades stagger angles (fields of pressure and velocity and global results like forces, torques and power coefficient on each blade with time).

Author Company: 
LML, UMR CNRS 8107, Arts et Metiers PARISTECH
Author Name: 
Bayeul Annie-Claude
Simonet Sophie
Dockter Aurore
Bois Gérard
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