COMPUTATIONAL ANALYSIS OF WIND FLOW IN ARRAYS OF MICRO-TURBINES SAVONIUS

1. A. Sánchez-Sibaja,J. Álvarez-Cedillo, J. C. Herrera-Lozada, M. Olguín Carbajal.Instituto Politécnico Nacional, Centro de Innovación y Desarrollo Tecnológico en Computo, Departamento de Posgrado, Área de procesamiento paralelo, México, D.F. Abstract Due to increased interest in the application of renewable energy, wind energy has been increased attention by researchers. Studies have been conducted in order to improve the aerodynamic performance of vertical turbines such as both Darrieus and Savonius turbine, so that in this article provides a computational analysis of the impact of wind on different geometric configurations of Savonius turbine proposed and studied previously. It also proposes a Savonius turbine respecting its original profile, subjected to a comparative analysis of its performance against conventional turbines. Following the results of comparative analysis between the turbines, it makes a new flow analysis on micro-turbines arrangements with these turbines, thus highlighting the proposed new turbines Savonius their lower residual turbulence. The dimensions of the turbines are suited to the geometric relationships previously analyzed and proposed in such a way that respects the original profile of each turbine. The size of each turbine is small since its application is proposed for power generation at low power arrangements that can be placed on mobile devices, taking advantage of the wind energy offers because of the resistance to displacement of the mobile. . Keywords: Wind Energy, Turbine Savonius, low-power turbines, aerodynamics, fluid analysis Introduction A wind turbine is a device that converts the kinetic energy of wind into rotational kinetic energy, and this in turn into electrical energy. Wind turbines have the advantage of being modular and can be installed relatively quickly which makes it a source of power generation attractive compared to other types of alternative energies such as hydropower. There are many different types of wind turbines and they can be divided into two large groups of turbines depending on the orientation of its rotation axis: wind turbines with horizontal axis and wind turbines with vertical axis , latter being the most competitive, if we consider factors such as the ability to capture the wind in any direction, are comparatively simple structure, easy maintenance and low cost of implementation and installation. Among the turbines vertical axis wind turbine is the Savonius, which was created by the Finnish engineer S.J. Savonius in 1931 as a drag on wind turbine vertical axis. The configuration of this turbine is a cross section in the form of "S" built by two semicircular blocks with a small overlap between them. Its principle of operation is based on the difference in drag between convex and concave parts of the turbine. In this article we perform a computational analysis of Savonius turbine flow with different geometric configurations [6],[9], observing the behavior of the air flow that strikes them, determining the best configuration for their application in modular systems mounted on mobile devices. Figure1. Savonius turbine Geometricconfigurations Studies both experimental and numerical have been done on the geometric variables of a Savonius turbine in order to improve performance and make better use of wind power. • Computational analysis of flow over the Savonius turbine. • The computational tool used for this analysis is the SolidWorks Flow Simulation, because studies of different research areas supporting the accuracy of physical development with simulations using SolidWorks utilities. To perform the following simulations, the software is configured with a total of 1500 flow lines in order to able to appreciate the trade wind. It implements a rectangular wind tunnel of 80 x 100 mm with a length of one meter, in which the Savonius turbines are positioned in the middle of the tunnel for testing. The fluid used is air at a speed at the entrance of 10 m / s with a laminar flow with low turbulence of 2%, the end of the tunnel is configured with Pascal 101325 environmental pressure at a temperature of 293.2 Kelvin degrees. • Figure 5. Flow paths on the different 3D Savonius turbines • Results • Due to the simplicity of the comparison with air flow paths in Figure 5, Figure 6 shows a comparison of the behavior of each turbine with different incidence angles in the air, these angles are 0 °, 45 ° , 90 °, and finally 135 °. The incidence of the wind at 180 ° is identical to the incidence at 0 °. • References • [6] M.A. Kamoji and S.B. Kedare and S.V. Prabhu, "Experimental investigations on single stage modified Savonius rotor", Applied Energy, Vol. 86, No. 7-8, Sept. 2008, pp. 1064 – 1073. • [9] Jean-Luc Menet and NachidaBourabaa, “Increase in the savonius rotors efficiency via a parametric investigation”, presented at the Conf. European wind energy, London, U.K., 2004. • Savonius turbines with different position. • Figure 2. Section in experimental research conducted by M.A. Kamoji et al. [6]. • Figure 3. Section of parametric investigation Furthermore J-L Menet et al. [9] • Our proposal • This article takes up the profile shown in Figure 3, we make a twist that causes a 180° on its own axis, this variation is of great interest because of its specific form does not exist in any position to stop the wind impinging on the concave section of the turbine regardless of wind direction, however the recruitment section is reduced considerably compared with Savonius turbines untwisted, which have the disadvantage of requiring specific positions in which they give greater uptake of wind. • Figure 4. 3D Model of twisted Savonius turbine proposed • Figure 6. Behavior of incident wind on different COMPUTATIONAL ANALYSIS OF WIND FLOW IN ARRAYS OF MICRO-TURBINES SAVONIUS