3D CFD Modelling of Performance of a Vertical Axis Turbine

Abstract

Recently, wind turbine research has switched focus to vertical axis wind turbines due to the extensive research that has been performed on horizontal axis wind turbines and the potential of vertical axis wind turbines in built-up areas. This study aims to analyse the performance of a small-scale hybrid vertical axis wind turbine that can switch from functioning as a Darrieus (lift) turbine to a Savonius (drag) turbine by rotating the blades. The turbine was analysed using 3D computational fluid dynamics (CFD) simulations in ANSYS Fluent as the primary method, and the findings were verified using wind tunnel experiments. During the analysis, design parameters such as the blade length, diameter, and number of blades were varied to determine if the design had room for improvement. It was found that the current design of the turbine has an optimal efficiency of 12.5% in the Darrieus configuration, which was found to increase when the diameter or blade length was increased. The Savonius configuration was found to be more efficient at low tip-speed ratios (<0.14), and its efficiency could be increased by adding more blades. The experiments found similar trends to the simulations; however, the efficiencies obtained were on average a tenfold increase from the simulation. Implementing the changes that increased efficiency leads to an increased wake recovery distance, making it less suitable for use in a wind farm.

Performance Rating and Flow Analysis of an Experimental Airborne Drag-Type VAWT Employing Rotating Mesh

“…Our findings, which demonstrate favorable performance compared to similar investigations on Savonius Drag-Type Vertical Wind Turbines, align well with the literature. Specifically, Gerrie et al [11] reported Cp values ranging from 0.12 to 0.14, Al-Gburi et al [15] reported a range from 0.10 to 0.21, Mohamed et al [21] reported a range from 0.10 to 0.25, Shukla et al [14] reported a range from 0.23 to 0.27, and Alom et al [41] reported a range from 0.11 to 0.33. However, it is crucial to acknowledge that each study involves a unique geometry, conditions, and experimental setups, which can influence the observed outcomes.…”

“…Their study categorized prototypes developed by universities and companies worldwide based on system architecture, highlighting both proven hardware configurations and potential future implementations. Gerrie et al [11] presented recent experimental and computational results for three-bladed Darieus and three-bladed Savonius VAWTs. The computational results demonstrate a significant difference from the experimental results, with an order of magnitude discrepancy.…”

Fast Power Coefficient vs. Tip–Speed Ratio Curves for Small Wind Turbines with Single-Variable Measurements following a Single Test Run

“…For a single turbine model, the performance was determined, and this was followed by measurement of the wind characteristics including velocities, turbulence intensities, and correlation in the wake flow field. Gerrie et al [38] performed 3D modeling of the performance of a VAWT. They employed Computational Fluid Dynamic (CFD) simulations and verified the results with wind tunnel experiments.…”

Numerical Investigations on the Transient Aerodynamic Performance Characterization of a Multibladed Vertical Axis Wind Turbine

“…Especially in urban environments, HAWTs are not a feasible option and thus pave the way for adopting vertical axis wind turbines (VAWTs). VAWTs can operate at much lower wind speeds with high turbulence levels due to their lower startup torque and omnidirectionality [3], making them a suitable and commercially viable option in urban settings [4]. Moreover, their lower cut-in speed allows them to have enhanced aerodynamic performance in non-uniform wind environments where flow restrictions, such as buildings, create further air turbulence [5,6].…”