COMPUTATIONAL ANALYSIS OF WIND FLOW IN
ARRAYS OF MICRO-TURBINES SAVONIUS
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 microturbines 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.
.
Computational analysis of flow over the
Savonius turbine.
Figure 2. Section in experimental research conducted by
M.A. Kamoji et al. [6].
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.
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.
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 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
Figure 4. 3D Model of twisted Savonius turbine proposed
[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 Nachida Bourabaa, “Increase in
the savonius rotors efficiency via a parametric
investigation”, presented at the Conf. European wind
energy, London, U.K., 2004.
Figure1. Savonius turbine
Geometric configurations
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.
Figure 6. Behavior of incident wind on different
Savonius turbines with different position.