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Delegates are invited to meet and discuss with the poster presenters during the poster presentation sessions between 10:30-11:30 and 16:00-17:00 on Thursday, 19 November 2015.

Lead Session Chair:
Stephan Barth, ForWind - Center for Wind Energy Research, Germany
Ivo Marinić-Kragć FESB, Croatia
Co-authors:
Ivo Marinić-Kragć (1) F
(1) FESB, Split, Croatia

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Presenter's biography

Biographies are supplied directly by presenters at EWEA 2015 and are published here unedited

I'm currently working on my Ph.D in Mechanical Engineering at Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture,Split, Croatia. To date i have published one scientific paper on Multi-Regime Shape Optimization of Fan Vanes for Energy Conversion Efficiency Using CFD, 3D Optical Scanning And Parameterization. Since then i have written two more scientific papers that are currently in revision process. My research intrests are Numerical optimization, Coupling of shape optimization and numerical analysis, Parameterizations of 3D shape for numerical optimization and Enhanced reverse re-engineering.


Poster

Poster Download poster (11.93 MB)

Abstract

Numerical workflow for 3D shape optimization and synthesis of Vertical-Axis Wind Turbines for specified operating regimes

Introduction

As the world continues to use up nonrenewable energy resources, wind energy will continue to gain popularity since it is renewable, pollution-free and inexhaustible. Two major types of wind turbines exist, more common is the horizontal-axis wind turbine (HAWT) although recently, Vertical-Axis Wind Turbines (VAWT) have been gaining popularity due to increased interest in personal green energy solutions. VAWTs target individual homes, farms, or small residential areas as a way of providing local and personal wind energy. VAWTs are quiet, can take wind from any direction and are easy to install which meets the demands of individual users willing to use wind energy technology in urban environments. There are new types of VAWTs emerging in the wind power industry which are a mixture between the Darrieus and Savonius designs.

Approach

The aim of this paper is to develop a computational framework for the shape optimization of vertical-axis wind turbines for single and variable operating conditions specified by local wind speed distributions. This computational framework enables optimizers to construct and evaluate shapes of VAWTs such as the Darrieus and Savonius but also to invent and synthesize new geometries custom shaped for specific locations. This is enabled by the single B-spline surface based shape parameterization developed in this paper specifically for VAWT design. The developed approach to modeling 3D shapes enables optimizers to use the same shape parameterization with as little as ten shape parameters. A small number of parameters is crucial for the optimization procedure since global shape optimization based on genetic algorithm is adopted in this paper. Reduction of the number of parameters is commonly accompanied by a loss in shape generality and therefore a reasonable compromise was established. The proposed definition of excellence is the respective annual energy production for given wind speed distributions. The numerical workflow consists of an efficient geometry parameterization, genetic algorithm based optimizer and a computational fluid dynamics based simulator. This workflow also has to implement the coupling of the process flows in addition to passing data amongst the individual applications including the corresponding data mining.

Main body of abstract

Various computational models that attempt to accurately predict the performance of a wind turbine and include momentum models, vortex models, and computational fluid dynamics (CFD) models. This paper will use CFD due to results that compare favorably with experimental data and required flexibility in the framework of analyzing the complex shapes that can be generated by the optimization procedure. A computationally efficient full 3D, transient CFD model was developed in off-the-shelf CFD software and numerous mesh tests were conducted with various vertical wind turbine geometry designs. Excellent agreement was obtained with experimental data existing in literature while maintaining low computational time and low mesh sensitivity.
Several case studies are presented with promising results towards the aspired custom-shaped vertical wind turbines for optimum performance for any given specific location. The first category of the case studies was aimed at improving already existing designs of Savonius and Darrieus wind turbines. The second category of the case studies was optimization for selected operating conditions with full freedom assigned to the optimizer to synthesize any shape. The developed computational workflow can therefore be seen as a numerical device for custom optimization of performance of renewable energy systems.


Conclusion




Learning objectives