Experimental And Numerical Investigation Of Aerodynamic Performance For Vertical Axis Wind Turbine Models With Various Blade Designs

Author's abstract: The demand for wind energy as a renewable source is rising substantially. A growing interest exists in utilizing potential energy conversion applications in areas with less powerful and less consistent wind conditions. In these areas, vertical-axis wind turbines (VAWTs) possess several advantages over the conventional horizontal-axis type. Savonius turbines are drag-based rotors which operate due to a pressure difference between the advancing and retreating blades. These turbines are simpler in design, less expensive to install, non-dependent of wind direction, and more efficient in lower wind speeds. In the present study, six different rotor designs with equal swept areas are analyzed with wind tunnel testing and numerical simulations. These models include a traditional Savonius with 2 blades, “CC” model, “QM” model, and 90 degree helical twist models with 2, 3, and 4 blades. The models were designed using the CAD software SolidWorks. Due to the complex geometry of the blades, the physical models were then 3D printed for experimental testing. Subsonic, open-type wind tunnel testing was used for measuring RPM and reactional torque over a range of wind speeds. For the numerical approach, ANSYS Fluent simulations were used for analyzing aerodynamic performance by utilizing moving reference frame and sliding mesh model techniques. For the models with helical twist, the cross-sections of the blades varies in the Y-direction. Because of this, a 3-dimensional and transient method was used for accurately solving torque and power coefficients. The 5 new rotor geometries included in the study create a center of pressure further from the axis of rotation causing greater torque on the turbine shaft, compared to the traditional Savonius turbine. The CC and QM cross-sections reduce the total range of negative torque on the blades by 20 degrees, compared to the traditional Savonius model. Helical designs better spread the applied torque over a complete revolution resulting in positive torque over all operational angles. Helical models with 2 and 3 blades have the best self-starting capability in low wind speeds. Under no generator loading, Helical3 begins rotation of 35 RPM at just 1.4 m/s wind velocity. The highest power coefficient in the study is achieved, both experimentally and numerically, by the helical VAWT with 2 blades. Averaged over one full rotation, a maximum power coefficient of 0.14 is observed with the Helical2 model at tip-speed ratio of 0.475.

Author's abstract: Savonius wind turbine is the simplest type of vertical axis rotor that has a relatively low efficiency. Operation of the Savonius wind turbine is based on the difference of the drag force on its semi-spherical blades, depending on whether the wind is striking the convex or the concave part of the blades. This turbine is being used in various countries around the world due to the simplistic design, cheap technology for construction, and a good starting torque independent of wind direction at low wind speeds. Due to its simple design and low construction cost, this rotor is mainly used for water pumping as well as wind power on small scale. The main goal of this current research is to investigate the aerodynamic performance of Savonius wind turbine. Wind tunnel investigation was carried out to find the aerodynamic characteristics like, drag coefficient, torque coefficient, and power coefficient of three blade Savonius wind turbine rotor models with and without overlap ratio (ratio of overlap distance between two adjacent blades and rotor diameter, OR = a/D) at various Reynolds numbers. Numerical investigation was also carried out to find those aerodynamic characteristics. For numerical investigation, commercial computational fluid dynamic (CFD) software GAMBIT and FLUENT were used. Afterwards those two results were compared for verification. Three different models with different overlap ratio were designed and fabricated for the current study to find the effect of overlap ratios. The results from the experimental part of the research show a significant effect of overlap ratio and Reynolds number on the improvement of aerodynamic performance of the Savonius wind turbine. At higher Reynolds number turbine Model without overlap ratio gives better aerodynamic coefficients and at lower Reynolds number Model with moderate overlap ratio gives better results.

The depletion of global fossil fuel reserves combined with mounting environmental concerns has served to focus attention on the development of ecologically compatible and renewable alternative sources of energy. Wind energy, with its impressive growth rate of 40% over the last five years, is the fastest growing alternate source of energy in the world since its purely economic potential is complemented by its great positive environmental impact. The wind turbine, whether it may be a Horizontal Axis Wind Turbine (HAWT) or a Vertical Axis Wind Turbine (VAWT), offers a practical way to convert the wind energy into electrical or mechanical energy. Although this book focuses on the aerodynamic design and performance of VAWTs based on the Darrieus concept, it also discusses the comparison between HAWTs and VAWTs, future trends in design and the inherent socio-economic and environmental friendly aspects of wind energy as an alternate source of energy.

In today’s world, clean and robust energy sources are being sought to provide power to residences, commercial operations, and manufacturing enterprises. Among the most appealing energy sources is wind power—with its high reliability and low environmental impact. Wind power’s rapid penetration into markets throughout the world has taken many forms, and this book discusses the types of wind power, as well as the appropriate decisions that need to be made regarding wind power design, testing, installation, and analysis. Inside, the authors detail the design of various small-wind systems including horizontal-axis wind turbines (HAWTs) and vertical-axis wind turbines (VAWTs). The design of wind turbines takes advantage of many avenues of investigation, all of which are included in the book. Analytical methods that have been developed over the past few decades are major methods used for design. Alternatively, experimentation (typically using scaled models in wind tunnels) and numerical simulation (using modern computational fluid dynamic software) are also used and will be dealt with in depth. In addition to the analysis of wind turbine performance, it is important for users to assess the economic benefits of using wind power. An entire chapter of this book is devoted to this topic, as well as case studies that help elucidate the issues that you’ll need to consider, from siting and mechanical complications, to performance and maintenance.

This proceedings book is a collection of high-quality peer-reviewed research papers presented at the International Conference of Experimental and Numerical Investigations and New Technologies (CNNTech2020) held at Zlatibor, Serbia, from 29th June to 2nd July 2020. The book discusses a wide variety of industrial, engineering and scientific applications of the engineering techniques. Researchers from academia and industry present their original work and exchange ideas, experiences, information, techniques, applications and innovations in the field of mechanical engineering, materials science, chemical and process engineering, experimental techniques, numerical methods and new technologies.

This is an open access book. ICOSEAT 2022 was held on July 21–23, 2022 in Bangka Island, one of the wonderful places of Indonesia. Articles in the field of Agroindustry and Appropriate Technology 4.0; Environmental and Mining Engineering; Sustainable Development and Tourism Management; Agriculture and Food Engineering; and Marine, Aquaculture and Biological Science. ICOSEAT provides a forum for Academic, Business and Government to present and discuss topics on recent development in those fields.

This book gathers the peer-reviewed papers presented at the XXIV Conference of the Italian Association of Theoretical and Applied Mechanics, held in Rome, Italy, on September 15-19, 2019 (AIMETA 2019). The conference topics encompass all aspects of general, fluid, solid and structural mechanics, as well as mechanics for machines and mechanical systems, including theoretical, computational and experimental techniques and technological applications. As such the book represents an invaluable, up-to-the-minute tool, providing an essential overview of the most recent advances in the field.

Growing energy demand and environmental consciousness have re-evoked human interest in wind energy. As a result, wind is the fastest growing energy source in the world today. Policy frame works and action plans have already been for- lated at various corners for meeting at least 20 per cent of the global energy - mand with new-renewables by 2010, among which wind is going to be the major player. In view of the rapid growth of wind industry, Universities, all around the world, have given due emphasis to wind energy technology in their undergraduate and graduate curriculum. These academic programmes attract students from diver- fied backgrounds, ranging from social science to engineering and technology. Fundamentals of wind energy conversion, which is discussed in the preliminary chapters of this book, have these students as the target group. Advanced resource analysis tools derived and applied are beneficial to academics and researchers working in this area. The Wind Energy Resource Analysis (WERA) software, provided with the book, is an effective tool for wind energy practitioners for - sessing the energy potential and simulating turbine performance at prospective sites.

A review of the aerodynamics, design and analysis, and optimization of wind turbines, combined with the author’s unique software Aerodynamics of Wind Turbines is a comprehensive introduction to the aerodynamics, scaled design and analysis, and optimization of horizontal-axis wind turbines. The author –a noted expert on the topic – reviews the fundamentals and basic physics of wind turbines operating in the atmospheric boundary layer. He then explores more complex models that help in the aerodynamic analysis and design of turbine models. The text contains unique chapters on blade element momentum theory, airfoil aerodynamics, rotational augmentation, vortex-wake methods, actuator-line modeling, and designing aerodynamically scaled turbines for model-scale experiments. The author clearly demonstrates how effective analysis and design principles can be used in a wide variety of applications and operating conditions. The book integrates the easy-to-use, hands-on XTurb design and analysis software that is available on a companion website for facilitating individual analyses and future studies. This component enhances the learning experience and helps with a deeper and more complete understanding of the subject matter. This important book: Covers aerodynamics, design and analysis and optimization of wind turbines Offers the author’s XTurb design and analysis software that is available on a companion website for individual analyses and future studies Includes unique chapters on blade element momentum theory, airfoil aerodynamics, rotational augmentation, vortex-wake methods, actuator-line modeling, and designing aerodynamically scaled turbines for model-scale experiments Demonstrates how design principles can be applied to a variety of applications and operating conditions Written for senior undergraduate and graduate students in wind energy as well as practicing engineers and scientists, Aerodynamics of Wind Turbines is an authoritative text that offers a guide to the fundamental principles, design and analysis of wind turbines.