Aerodynamic Modeling and Performance Study of an INVELOX System Containing Multiple Wind Turbines Using a Semi-Analytical Approach

The INVELOX system is an innovative approach that offers improved energy absorption efficiency from wind flow and reduced costs by utilizing smaller wind turbines. This research focuses on investigating the steady-state performance of one, two, or three wind turbines arranged within the venturi section of the system. A comprehensive modeling approach using an improved Blade Element Momentum (BEM) theory is proposed and implemented as a MATLAB code. The code incorporates Prandtl’s tip and hub loss factors, as well as turbulent wake corrections. The accuracy of the code is validated against experimental and numerical data. The results demonstrate that in a three-rotor tandem configuration in the INVELOX system, the power extracted from the second and third turbines is 0.54 and 0.24 times the power of the first turbine, respectively. Furthermore, for a two-turbine arrangement in the venturi section, the total power extracted from the system is 53.9% higher than that of a single turbine layout. In the case of a three-turbine configuration, the total power increases up to 1.78 times compared to a single turbine. The proposed model is suitable for geometric optimization and parameter studies. The system’s performance is evaluated in terms of tip speed ratio, and the effects of different correction models are analyzed, including the local changes in forces and moments.