Abstract

Environmental pollution is the major concern for all. Renewable energy sources in particular wind and solar play a major role in mitigating pollution. Further to increase energy production by wind power, wind turbines are to be more efficient and should able to operate in low wind regimes. In this research work, the aerodynamic performances are evaluated for the bionic modified bumped blade of an S1223 airfoil. The numerical analysis is carried out with Ansys Fluent tool using turbulent-dissipation model. The aerodynamic performance characteristics such as lift coefficient, drag coefficient are computed and compared with the normal blade. The bionic bumped model produced 11 percent increase in lift coefficient, 20 per cent increase in drag coefficient for the maximum lift producing AoA. The numerically evaluated model can be verified bytesting on real time wind on the field.

Abstract

The aim of this paper is to describe the methodology followed in order to determine the viscous effects of a uniform wind on the blades of small horizontal-axis wind turbines that rotate at a constant angular speed. The numerical calculation of the development of the three-dimensional boundary layer on the surface of the blades is carried out under laminar conditions and considering flow rotation, airfoil curvature and blade twist effects. The adopted geometry for the twisted blades is given by cambered thin blade sections conformed by circular are airfoils with constant chords. The blade is working under stationary conditions at a given tip speed ratio, so that an extensive laminar boundary layer without flow separation is expected. The boundary layer growth is determined on a non-orthogonal curvilinear coordinate system related to the geometry of the blade surface. Since the thickness of the boundary layer grows from the leading edge of the blade and also from the tip to the blade root, a domain transformation is proposed in order to solve the discretized equations in a regular computational 3D domain. The non-linear system of partial differential coupled equations that governs the boundary layer development is numerically solved applying a finite difference technique using the Krause zig-zag scheme. The resulting coupled equations of motion are linearized, leading to a tridiagonal system of equations that is iteratively solved for the velocity components inside the viscous layer applying the Thomas algorithm, procedure that allows the subsequent numerical determination of the shear stress distribution on the blade surface.

Abstract

Abstract

The awareness for developing an eco-friendly industry based on green materials, sustainable technologies and optimum process with less environmental impact are a general societal consciousness, but it is still a considerable challenge to achieve. The biodegradable structural materials can contribute to reduce the CO2 emissions, the carbon footprint and increase the concept of recyclability for structural applications. In terms of performances, the natural fiber reinforced composite material could become in worthy alternative to E-Glass composite, wood reinforced materials and aluminum alloys because of their good ratio between mechanical properties, density and cost. However, the structural engineering applications are still very limited mainly because the lack of a robust manufacturing process. For that purpose, it has been developed an innovative mechanical extraction methodology based on the morphology of two species of bamboo, along with the optimization of the melting parameters to manufacture a fully biodegradable Bamboo-PLA composite. Furthermore, in order to define the future applications, the mechanical properties have been analyzed under different thermal cycling conditions.