Optimisation of vertical axis wind turbine: CFD simulations and experimental measurements

Abstract

A system for the conversion of kinetic energy of wind into thermal energy has been developed which can replace relatively expensive electromechanical equipment. The system consists of a vertical axis wind turbine (VAWT) which is coupled with the shaft of a stirred vessel. In the present work, computational fluid dynamic (CFD) simulations have been performed for the flow generated in a stirred tank with disc turbine (DT). The predicted values of the mean axial, radial and tangential velocities along with the turbulent kinetic energy have been compared with those measured by laser Doppler anemometry (LDA). Good agreement was found between the CFD simulations and experimental results. Such a validated model was employed for the optimisation of drag-based VAWT. An attempt has been made to increase the efficiency of turbine by optimising the shape and the number of blades. For this purpose, the combination of CFD and experiments has been used. The flows generated in a stirred tank and that generated by a wind turbine were simulated using commercial CFD software Fluent 6.2. A comparison has been made between the different configurations of wind turbines. Results show that a provision in blade twist enhances the efficiency of wind turbine. Also, a wind turbine with two blades has higher efficiency than the turbine with three blades. Based on the detailed CFD simulations, it is proposed that two bladed turbine with 30 • twist shows maximum efficiency.

Performance parameters of Savonius type hydrokinetic turbine – A Review

“…The angular acceleration of Savonius turbine increases, while the rotor moment, M, and inertia of the turbine decrease with increase of the aspect ratio [50]. There are a number of studies for the wind as well as for water as working fluid which reveal that aspect ratio ranging from 1.0 to 2.0 also exhibits good performance of Savonius rotors [39,47,[55][56][57][58][59][60][61][62][63].…”

“…Ghatage and Joshi [62] carried out a numerical study to find the optimum twist angle for Savonius rotor having two and three blades with aspect ratio of 2.0. The study resulted in maximum C P ¼ 0.216 at a twist angle of 30°for a two-bladed rotor and maximum C P ¼0.163 at a twist angle of 45°for three blades Savonius rotor.…”

Computational aerodynamic optimisation of vertical axis wind turbine blades

“…As a result they have not been interested in the effects of blade thickness, limiting the blades to be thin curves. This approach can be seen in Ghatage and Joshi [12] and Ypma [13], and is not appropriate for this study which considers both lift and drag.…”

Design and numerical analysis of an efficient H-Darrieus vertical-axis hydrokinetic turbine

“…Initial 2D CFD model with less computation cost that 3D model was used to represent the vertical hydrokinetic turbine and the water domain. Based on the review of relevant works [6,[50][51][52], it has been reported that a 2D model is sufficient in revealing the factors that influence the performance and majority of flow physics that surround the vertical-axis hydrokinetic turbine such as hydrofoil profile, N, σ, and D. In the 2D numerical study of this work, the effects from supporting arms were not taken into consideration. Unsteady Reynolds-Averaged Navier-Stokes (RANS) equations were solved using the SIMPLE algorithm for pressure velocity coupling [53][54][55][56].…”