CONSTRUCTAL DESIGN OF AN ONSHORE OVERTOPPING DEVICE IN REAL SCALE FOR DIFFERENT RAMP CONSTRUCTION AREAS
Jaifer Corrêa Martins1; Marcelo Moraes Goulart1; Jeferson Avila Souza1; Liércio André Isoldi1; Elizaldo Domingues dos Santos1; Mateus das Neves Gomes2; Luiz Alberto Oliveira Rocha3
1 Universidade Federal do Rio Grande; 2 Instituto Federal do Paraná, Campus Paranaguá; 3 Universidade Federal do Rio Grande do Sul
doi:10.20906/CPS/COB-2015-2255
Resumo
The study about technologies and operational principles of devices to convert wave energy into electrical one (WEC) has increased significantly. Among the studied WECs it is possible to mention the overtopping device. Its main operational principle consists on a ramp which guides the incoming waves into a reservoir raised slightly above the sea level. The accumulated water in the reservoir flows through a low head turbine generating electricity. In the present work it is performed a numerical study concerned with the effect of ramp geometry over the performance of an onshore overtopping device in real scale by means of Constructal Design. The purpose of this study is to evaluate the ratio between the areas of the ramp and tank (fi), and the ratio between the height and length of ramp (H1/L1) which maximizes the amount of water that enters into device reservoir. In all studied cases, one specific distance from the bottom of the tank to the bottom of device of S = 6.0 m is employed. The values of fi evaluated was: fi = 0.006, fi = 0.012 and fi = 0.024. For all studied cases the conservation equations of mass, momentum and one equation for the transport of volumetric fraction are solved with the finite volume method (FVM). To tackle with water-air mixture, the multiphase model Volume of Fluid (VOF) is used. Results showed that the best shapes, i.e., which maximizes the amount of water entering into the reservoir, were achieved for the lowest ratios of fi and H1/L1 for the evaluated depth. Moreover, the optimal geometry also changes with the variation of fi.
Palavras-chave: Constructal Design; Overtopping Device; Geometric optimization; Numerical Study