EE - Trabalhos apresentados em eventos
URI permanente para esta coleçãohttps://rihomolog.furg.br/handle/1/515
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Resultados da Pesquisa
- ItemSimulação numérica de um dispositivo de aproveitamento da energia das ondas do tipo coluna de água oscilante: comparação de dois códigos numéricos(2010) Conde, José Manuel Paixão; Teixeira, Paulo Roberto de Freitas; Didier, Eric LionelNeste artigo apresentam-se os resultados da aplicação de dois códigos numéricos na simulação de um dispositivo de aproveitamento da energia das ondas do tipo coluna de água oscilante. Um dos códigos (FLUINCO) é baseado na técnica dos elementos finitos e o outro (FLUENT) na técnica dos volumes finitos. O objectivo do trabalho consiste na validação destes códigos para este tipo de escoamento, com o intuito de os aplicar de forma sistemática no projecto de sistemas de aproveitamento de energia das ondas. O caso simulado, que corresponde a um modelo simplificado testado experimentalmente, permitiu concluir da boa qualidade dos resultados obtidos, existindo uma boa correspondência entre os resultados experimentais e os obtidos pelos códigos numéricos.
- ItemNumerical analysis of regular waves over an onshore oscillating water column(2010) Davyt, Djavan Perez; Teixeira, Paulo Roberto de Freitas; Ramalhais, Rúben dos Santos; Didier, Eric LionelThe potential of wave energy along coastal areas is a particularly attractive option in regions of high latitude, such as the coasts of northern Europe, North America, New Zealand, Chile and Argentina where high densities of annual average wave energy are found (typically between 40 and 100 kW/m of wave front). Power estimated in the south of Brazil is 30kW/m, creating a possible alternative of source energy in the region. There are many types and designs of equipment to capture energy from waves under analysis, such as the oscillating water column type (OWC) which has been one of the first to be developed and installed at sea. Despite being one of the most analyzed wave energy converter devices, there are few case studies using numerical simulation. In this context, the numerical analysis of regular waves over an onshore OWC is the main objective of this paper. The numerical models FLUINCO and FLUENT® are used for achieving this goal. The FLUINCO model is based on RANS equations which are discretized using the two-step semi-implicit Taylor-Galerkin method. An arbitrary lagrangean eulerian formulation is used to enable the solution of problems involving free surface movements. The FLUENT® code (version 6.3.26) is based on the finite volume method to solve RANS equations. Volume of Fluid method (VOF) is used for modeling free surface flows. Time integration is achieved by a second order implicit scheme, momentum equations are discretized using MUSCL scheme and HRIC (High Resolution Interface Capturing) scheme is used for convective term of VOF transport equation. The case study consists of a 10.m deep channel with a 10 m wide chamber at its end. One meter high waves with different periods are simulated. Comparisons between FLUINCO and FLUENT results are presented. Free surface elevation inside the chamber; velocity distribution and streamlines; amplification factor (relation between wave height inside the chamber and incident wave height); phase angle (angular difference between the wave inside and outside the chamber); and sloshing parameter to quantify it inside the chamber are analised. Finally, a discussion of the potential and limitations of each numerical model as well as the behaviour of the onshore OWC device is presented.
- ItemTwo-dimensional geometric optimization of an oscillating water column converter of real scale(2013) Gomes, Mateus das Neves; Santos, Elizaldo Domingues dos; Isoldi, Liércio André; Rocha, Luiz Alberto de OliveiraThe present paper presents a two-dimensional numerical study about the geometric optimization of an ocean Wave Energy Converter (WEC) into electrical energy. The operational principle is based on the Oscillating Water Column (OWC). The main goal is to seek for the optimal geometry which maximizes the absorbed power take off (PTO) when it is subjected to a defined wave climate. To do so, Constructal Design is employed varying the degree of freedom (DOF) H1/L (ratio between the height and length of OWC chamber) and H3 (lip submergence), while the other DOF H2/l (ratio between height and length of chimney) is kept fixed. Moreover, the chamber and total areas of OWC device are also kept fixed, being the problem constraints. In this study was adopted a regular wave with real scale dimensions. For the numerical solution it is used the Computational Fluid Dynamic (CFD) commercial code FLUENT®, based on the Finite Volume Method (FVM). The multiphasic Volume of Fluid (VOF) model is applied to tackle with the water-air interaction. The computational domain is represented by an OWC device coupled with the wave tank. The results led to a theoretical recommendation about the chamber geometry which maximizes the device performance, indicating that the higher efficiency (around 40 %) is obtained when H1/L = 0.13 and H3 = 9.50 m. On the other hand, the chamber geometry that generate the lower efficiency (around 4.4 %) is formed by H1/L = 0.03 and H3 = 9.00 m. One can note that the optimal shape is approximately 10 times more efficient than the worst geometry, showing the applicability and relevance of the Constructal Design method in the design of OWC-WEC.
- ItemNumerical simulation of an owc devise(2013) Souza, Jeferson Avila; Santos, Elizaldo Domingues dos; Isoldi, Liércio AndréWave energy is a renewable and clean energy resource that, in a near future, may become an alternative to the more pollutant fuels. There are a number of wave energy converters prototypes and a few installed text facilities, however there is no device ready for commercial utilization. In this work an Oscillation Water Column Generator (OWC) is numerical simulated using the OpenFOAM software. The VOF (volume of fluid) method is used to solve the multiphase (air + water) fluid flow problem. Regular gravity waves, inside a rectangular (2D) tank, are imposed numerically by prescribing the inlet velocity at the left wall of the tank. The main goal of the work is to simulate the interaction between the generated waves and the OWC device and calculate the energy generated by the turbine (usually a Wells turbine). The air turbine, responsible for the electrical energy generation, is simulated by applying a source (force) term to the momentum equation at the OWC chimney section. Pressure drop at the turbine and air velocity at the chimney outlet section are evaluated as a function of time and used to compute the available energy to be converted into electrical energy. Results are presented and compared for two operating condition: with turbine and without turbine.