Modeling of a wind energy harvesting INVELOX system by combination of numerical results and semi-analytical framework

Abstract

In the current study, the 3D mesh generation and numerical solution of the flow within an INVELOX system, a modern wind energy harvesting structure, was presented. Based on the numerical results, a semi-analytical BEM framework was developed to model the aerodynamics and to estimate the performance characteristics of the system. It is implemented via an offline coupling mechanism. A particular and optimum blade shape was designed to be installed in the venture section of the INVELOX system. It was performed based on the prescribed sections mentioned in the literature. Considering the Prandtl's tip and hub loss factors as well as the Glauert’s and Berton turbulent wake corrections, the behavior of the power coefficient and force coefficients were depicted. A comprehensive study was organized in terms of the tip speed ratio and the normalized length or dimensionless radius. From validation study, it was concluded that both numerical and analytical approaches were in acceptable agreement with the experimental and prior approved data. Based on these results, one may deduce that wind velocity can be magnified by about 70 percent by the Invelox system in the venture section. It is considerably more than the traditional ducts or shrouds used for wind acceleration. In order to make a comparison among the turbulent wake correction formulas, according to the proposed semi-analytical code results, it was found that the Berton and Glauert models would make a maximum difference of 15 percent when the power estimation was expected. By using this proposed hybrid model and related numerical and analytical frames, it is definitely possible to conduct the optimization study considering all the geometric and environmental parameters.

Keywords

• wind energy
• invelox system
• numerical solution
• semi-analytical code
• prandtl correction
• turbulent wake correction