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Simulations de l'accumulation de glace sur un cylinder cas test pour le givrage des eoliennes

Posted on:2013-09-26Degree:M.Sc.AType:Thesis
University:Universite du Quebec a Rimouski (Canada)Candidate:Martini, FahedFull Text:PDF
GTID:2452390008972321Subject:Environmental Engineering
Abstract/Summary:
This project has been conducted in the context of intensifying the knowledge of atmospheric icing on wind turbines to be adapted in Nordic conditions. The main objective is to develop techniques to evaluate the long-term impact of icing on the performance of wind turbine projects and to optimize the de-icing techniques.;The ability of an object to capture water droplets presented in an air flow is caIled collection efficiency. Evaluation of the collection efficiency over a cylinder has been simulated using Eulerian approach based on multi-phase turbulence models in CFX. The results have been validated with those of Lagrangian and Eulerian approaches in FLUENT as weIl as with experimental results obtained from previous studies. The results showed that the use of ANSYS-CFX multi-phase models was effective in simulating water volume fractions through the domain and in defining the collection zone and the impingement limits around the cylinder. In addition, a code to calculate the trajectories of supercooled water droplets in the air intercepted by a cylinder has been achieved using MS-Excel sheets supported with VBA (Visual Basic for Applications). This interface has been used to demonstrate different scenarios that can help to validate similar simulations using CFX. In both Excel and CFX simulations, the streamlines and trajectories have demonstrated similar behaviour which is consistent with the forces acting on water droplets.;Several upstream complex studies are to be conducted prior to propose a precise model capable of achieving a three-dimensional simulation of icing on wind turbine rotating blades. In order to overcome these difficulties, we made use of the high capacity of commercial CFD software, together with the friendly user interface of MS-Excel. The validation of these tools for the ice accretion past a cylinder is the prerequisite for applying these tools for the 3D simulation of icing over wind turbines, given that the study of cylinder icing is fundamental in several areas of icing research.
Keywords/Search Tags:Cylinder, Icing, Wind, Simulations
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