Abstract
To clarify the behavior of the blade tip vortices of a wind turbine equipped with a brimmed-diffuser shroud, called a “Wind-Lens turbine”, we conducted a three-dimensional numerical simulation using a large eddy simulation (LES). Since this unique wind turbine consists of not only rotating blades but also a diffuser shroud with a broad-ring brim at the exit periphery, the flow field around the turbine is highly complex and unsteady. Previously, our research group conducted numerical simulations using an actuator-disc approximation, in which the rotating blades were simply modeled as an external force on the fluid. Therefore, the detailed flow patterns around the rotating blades and the shroud, including the blade tip vortices, could not be simulated. Instead of an actuator-disc approximation, we used a moving boundary technique in the present CFD simulation to simulate the flow around a rotating blade in order to focus especially on blade tip vortices. The simulation results showed a pair of vortices consisting of a blade tip vortex and a counter-rotating vortex which was generated between the blade tip and the inner surface of the diffuser. Since these vortices interacted with each other, the blade tip vortex was weakened by the counter-rotating vortex. The results showed good agreement with past wind tunnel experiments.
Highlights
To help solve energy problems and mitigate global warming, the importance of clean, renewable energy is growing
The blade tip vortex and the induced vortex are mutually weakened in this process and dissipate before they reach the end of the diffuser
The blade tip vortex and the induced vortex are mutually weakened in the above process, they do not dissipate before they reach the end of the diffuser because the diffuser length is shorter than that of the long-type diffuser and is shorter than the distance required for the vortices to dissipate
Summary
To help solve energy problems and mitigate global warming, the importance of clean, renewable energy is growing. In order to prevent massive blackouts caused by disasters, small distributed energy systems have been and continue to be tested In this testing, there has been an increase in the variety of technologies used to generate clean, renewable energy. In addition to increased power output, a Wind-Lens turbine offers the following advantages: low noise, reduced number of bird strikes, and reduced landscape disturbance. We conducted numerical simulations of the flow around a Wind-Lens turbine, paying special attention to the behavior of the blade tip vortices. Numerical simulations of the flow around a Wind-Lens turbine have been conducted previously, almost all of these simulations used the Reynolds-averaged Navier-Stokes (RANS) technique This numerical technique modeled a wind turbine as a simple resistance in the inflow direction [8,9]. In the present paper, we use a moving boundary technique in the CFD model to simulate the flow around the rotating blades
Sign-in/Register to view highlights & summary 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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
