Computational Analysis of Symmetric and Cambered Blade Darrieus Vertical Axis Wind Turbine With Bio-Mimicked Blade Design

Vertical axis wind turbine suffers from low performance, and the need for improvement is a challenge. This work addresses this problem by using computational fluid dynamics. This chapter aims to analyze and compare symmetric and cambered Darrieus turbine. These analyses are usually carried for straight leading-edge blades, and cambered resembles more the natural shape of the wing of birds and other aquatic mammals, which helps them generate extra lift during movement. Moreover, recent studies suggest better performance was observed for NACA0018 symmetric aerofoil blades, and a similar trend has been observed for NACA2412 cambered aerofoil profiles. Turbine models having symmetric NACA0018 and cambered NACA2412 profiles have been studied. By comparing the symmetric model with cambered blade models, differences in coefficient of torque have been presented. OpenFOAM is used for performing the 2D simulation with dynamicOverset-FvMesh for motion solver with overset mesh method. Meshed geometry was constructed with GMSH codes and the simulation uses overPimpleDyMFoam algorithm as a solver.

Simulating NACA Equations Used in Optimizing Wind Turbine Blade Design: محاكاة معادلات NACA واستخدامها لتحسين تصميم شفرة العنفة الريحية

Aerodynamic scientists are interested in geometry definition and possible geometric shapes that would be useful in design. This paper illustrates a simulation of a NACA four digits airfoil blade profile using MATLAB. As airfoil design became more sophisticated, this basic approach has been modified to include additional variables, and suggestions for the chord line length at the root and at the end of the blade. as well as changes in the twisting angle of the blade and its thickness, this helps to reduce the weight of the blade significantly Simulating NACA equations is very useful in obtaining coordinates of airfoil curvature for the whole series of NACA four digits, which is very effective in optimizing blade design. In order to get an optimal operating performance and high efficiency for the airfoil, the blade surface must be smooth and does not suffer any discontinuities or undefined cases, which cause separation of the boundary layer during the airflow, and get as a result great energy losses. Therefore, the conditions for the continuity of the blade was extracted using mathematical analysis, so the air flow does not suffer any interruptions which reduce the efficiency. This enable us to determine the locations of the maximum thickness of the blade sections on the chord along the blade, in addition to specifying conditions for the chord line length at the root and at the end of the blade which keep the blade curvature continuous and doesn’t have any irregular points, which also facilities writing the necessary programs.

Performance of a HAWT Rotor with a Modified Blade Configuration

As the world focuses more on clean and green Earth, wind energy plays a significant role. Wind energy is a renewable source of energy that can cope with the ongoing global fossil fuel crisis. The wind energy converters like wind turbines have been studied a lot in terms of design and performance. The current work includes analyzing the output effects of a horizontal axis wind turbine (HAWT) with a modified blade configuration at specific wind speeds. A numerical investigation is carried out using two different numerical software on the chosen airfoil used in blade design validated with the analysis carried out in open-loop wind tunnels. The study is divided into two phases: first, the selected airfoil is tested experimentally and using CFD, and then the findings are compared to those of the University of Illinois Urbana Champaign wind tunnel tests at low Reynolds numbers. The second phase includes the numerical analysis based on the blade element momentum method and non-linear lifting line simulations of modified blade design at high Reynolds number. The numerical results of rotor performance analysis have been compared to existing experimental results. The findings of all numerical investigations agree with those of the experiments. An optimal value of the power coefficient is obtained at a particular tip speed ratio close to the desired value for large wind turbines. For maximum power, this study investigates the optimum pitch angle. The work demonstrated the improved HAWT rotor blade design to produce better aerodynamic lift and thus improve performance.

THEORETICAL METHOD OF THE OPTIMUM DESIGN OF A SUPERCAVITATING PROPELLER BLADE WITH SPOILER MOUNTED ON THE TRAILING EDGE

This paper presents theoretical design method to obtain 2-D optimum section with spoiler mounted on the trailing edge of a supercavitating propeller blade. Matched Asymptotic Expansions (MAE) is applied to determine the geometry of profile and cavity shape in the framework of potential flow theory. The blade section is of wedge-like shape and the opened cavity closure scheme is adopted. A typical section, on which the optimum blade design will be based, is singled out among the best individual sections from root to tip. The spoiler length of each hydrofoil section resulting from MAE method are finalized with CFD method so as to consider viscous effect under the same lift condition, others hydrofoil geometries being kept constant. The hydrodynamic performances of all blade sections being designed on the basis of the resulting typical section from linearized method are finally predicted with CFD method.

Design, fabrication, and testing of an active camber rotor blade tip

This paper presents a morphing blade design for wind turbine application with flexibility in chord-wise bending while providing sufficient stiffness to carry the aerodynamic loads. The NACA64 profile is selected for the camber morphing blade demonstrator. A corrugation concept is chosen because it is relatively easy to manufacture and provides sufficient stiffness to resist deformation due to the aerodynamic loads (through the provision of effective stringers) while providing the required flexibility for chord-wise bending. A mechanical actuation mechanism is employed to achieve the desired morphing angle and increase the stiffness of the morphing airfoil section to resist aerodynamic loading. The design of a morphing blade demonstrator is presented together with the manufacturing process. Finally, an experimental study is conducted where the morphing angle is measured for increasing actuation load and compared with FE analysis showing good agreement between the experimental results and results from the finite element analysis in addition to achieving the desired morphing angle.

Design, Analysis and Development of Digging and Roller Chain Conveying System for Self-Propelled Onion Harvester

The history of Agriculture in India dates back to Indus Valley Civilisation. India ranks second worldwide in farm outputs. As of 2018, agriculture employed more than 50% of the Indian workforce and contributed 17–18% to the country's GDP. India has the largest net cropped area, followed by the US and China, yet mechanization in farming is comparatively low compared to developed countries. The lack of technological development and unaffordability of new and competent machines for the average farmer are the few of the reasons for this encumbrance. The development of the onion harvester intends that it will provide a reliable and affordable alternative to traditional farming practices. The digging and conveying systems are the integrated part of the onion harvester. The design of the blade and conveyor is made by using CATIA V5 and analysis of the parts are done using ANSYS Workbench. During design and analysis, severe factors are considered such as preventing the damage to onion bulbs, size of bulbs, soil condition, onion leaves at a predetermined height and roots of the crops to penetrate. This paper is intended to discuss the results of the design and analysis of the digging and conveying systems under the guidelines of the SAE TIFAN rulebook [1]. Keywords: Onion Harvester, Blade Design, Conveyor Design, FEA Analysis.

Wind Tunnel Tests of a Model Small-scale Horizontal-axis Wind Turbine Developed from Blade Element Momentum Theory

The small-scale horizontal-axis wind turbines (SHAWTs) have emerged as the promising alternative energy resource for the off-grid electrical power generation. These turbines primarily operate at low Reynolds number, low wind speed, and low tip speed ratio conditions. Under such circumstances, the airfoil selection and blade design of a SHAWT becomes a challenging task. The present work puts forward the necessary steps starting from the aerofoil selection to the blade design and analysis by means of blade element momentum theory (BEMT) for the development of four model rotors composed of E216, SG6043, NACA63415, and NACA0012 airfoils. This analysis shows the superior performance of the model rotor with E216 airfoil in comparison to other three models. However, the subsequent wind tunnel study with the E216 model, a marginal drop in its performance due to mechanical losses has been observed.