Parametric Study on a Performance of a Small Counter-Rotating Wind Turbine

Michał Pacholczyk; Dariusz Karkosiński

doi:10.3390/en13153880

Parametric Study on a Performance of a Small Counter-Rotating Wind Turbine

Abstract

A small Counter-Rotating Wind Turbine (CRWT) has been proposed and its performancehas been investigated numerically. Results of a parametric study have been presented in this paper.As parameters, the axial distance between rotors and a tip speed ratio of each rotor have been selected.Performance parameters have been compared with reference to a Single Rotor Wind Turbine (SRWT).Simulations were carried out with Computational Fluids Dynamics (CFD) solver and a Large EddyScale approach to model turbulences. An Actuator Line Model has been chosen to represent rotors inthe computational domain. Summing up the results of simulation tests, it can be stated that whenconstructing a CRWT turbine, rotors should be placed at a distance of at least 0.5 D (where D is rotorouter diameter) or more. One can then expect a noticeable power increase compared to a singlerotor turbine. Placing the second rotor closer than 0.5 D guarantees a significant increase in power, butin such configurations, dynamic interactions between the rotors are visible, resulting in fluctuationsin torque and power. Dynamic interactions between rotor blades above 0.5 D are invisible.