Abstract
Vertical axis Darrieus turbine is the key component for ocean energy conversion and utilization. In the present work, the energy performance, flow pattern, and radial force for a vertical axis Darrieus turbine were investigated. The experimental measurements and numerical simulations were in good agreement, which validates the accuracy and reliability of the numerical method. The results showed that the power coefficient gradually increased with the increase of tip speed ratio λ, and the power coefficient had three peaks in a revolution of runner due to three blades. The complex vortex induced by the turbine revolution mainly includes the blade tip vortex and blade surface vortex, which are related to the turbine rotation and flow separation on blade surface. The vorticity transport equation was first introduced to analyze the mechanism and evolution of vortex in a vertical axis Darrieus turbine, and the results revealed that the relative vortex elongation term is the main driving force for the formation and development of the blade surface vortex. The radial force of the Darrieus turbine gradually increases with the increase in tip speed ratio, and it is symmetrical with three humps due to three blades.
Highlights
Global carbon dioxide emissions have been increasing every year because of the extensive use of traditional fossil energy, which has triggered the greenhouse effect and brought huge environmental problems
Benzerdjeb et al [10] discussed the influence of blade attack angle on its energy performance through experiments, and the results showed that when the blade angle was 1.75, the flow pattern was stable and the output power of turbine was the best
From a comparison of the instantaneous power of each blade at different tip speed ratios in Figure 6f, we found that when the tip speed ratio was below 2.0, the internal flow was dominated by a dynamic stall with the increase in the tip speed ratio
Summary
Global carbon dioxide emissions have been increasing every year because of the extensive use of traditional fossil energy, which has triggered the greenhouse effect and brought huge environmental problems. New types of clean, renewable, and sustainable energies are exploring and developing around the world [1,2]. Ocean energy, as a new type of renewable energy with great reserves, is focused and researched by scholars. The marine energy turbines are usually employed to develop ocean energy and are mainly divided into horizontal axis hydrokinetic turbines and vertical axis hydrokinetic turbines (VAHT). Compared with the horizontal axis hydrokinetic turbine, the VAHT is more suitable for the development and utilization of ocean tidal energy under complex ocean conditions in the deep sea due to its low cost and simple structure [3]. As an important type of VAHT, the Darrieus turbine has attracted attention because of its higher energy utilization rate. Kiho et al [4] did cross-strait experiments by installing a Darrieus turbine with a diameter of 1.6 m in the Kurushima Strait, the highest efficiency was 56% in the flow rate of
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call