Abstract
The aim of this study is to optimize and analyze the characteristics of the upwind primary rotor and the downwind secondary rotor of the contra rotor wind turbine to increase the aerodynamic performance by using computational fluid dynamic (CFD). The main objective is to provide maximum energy that can be extracted by the primary and secondary rotor from the renewable resource of wind to increase the thrust power. For this purpose, two kinds of rotor configurations which are 3-bladed single and 3-bladed contra-rotating rotor were compared by using CFD. The results of the primary and secondary rotor are validated with measurements of the 30 KW Contra rotor wind turbine available on literature and plotted for power output. The optimum axial distance between the two rotors are investigated through CFD for increased performance. In addition, the increased thrust and torque for each rotor configuration are compared for aerodynamic feasibility.
Highlights
Wind power is a significant promising source of renewable energy, and its conversion to usable energy is important considering the rapid decrease of fossil energy sources of earth
To validate the results based on computational fluid dynamic (CFD), the power output as given in Jung et al [7] for the 30 kW contra-rotating wind turbines (CRWT) is computed and compared to measured values [7]
In single rotor wind turbines (SRWT) for wind speed up to 6 m/s computationally calculated results approximately agree with the measured values [7] and after 6 m/s variation are predicted due to the extension bar provided for some distance in SRWT-CFD model comparing the experimental model
Summary
Wind power is a significant promising source of renewable energy, and its conversion to usable energy is important considering the rapid decrease of fossil energy sources of earth. According to Betz theory [5], the maximum energy conversion efficiency of conventional wind turbines having a single rotor is about 59%. The maximum efficiency obtained by contra rotors having the same area is increased to 64% [6] Based on these studies, in order to increase the power efficiency of wind turbines on contra-rotating wind turbines (CRWT) that have two rotors rotating in opposite direction coaxially have been carried out [7–15]. In order to increase the power efficiency of wind turbines on contra-rotating wind turbines (CRWT) that have two rotors rotating in opposite direction coaxially have been carried out [7–15] These studies are based on the various wind turbine energy assessments and comparison of power output in CRWT with that of SRWT. A comparison of 30 kW CRWT with SRWT is made using CFD prediction on power output (kW), thrust (N), and torque (N-m) for each rotor configurations (3-blade, 3-blade contra), and the aerodynamic improvement of a CRWT was considered
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