Optimal design of an horizontal axis wind turbine using blade element momentum theory

Abstract

The aerodynamic modelling of the wind turbine blades is a vital step in the design of the turbine. Several design methods are available for the aerodynamic design of the rotor, however, in this study a mathematical model based on blade element momentum concept is applied. the purpose of this work is to optimize the distribution of chord and twist angle along the blade span of a 20 KW HAWT using the BEM method, the blade design parameters such as the optimum lift and drag coefficient , chord and twist angle, the axial induction factor(a) and the angular induction factor(a’) of the designed HAWT are codified and estimated using the MATLAB software. The results of the analysis show on the one hand a decrease in chord length and twist angle along the blade length and on the other hand the maximum values that can be achieved by the axial and angular inductions factors are respectively 0.3325 and 0.175. This approach can be effectively implemented for the analysis of HAWTs operating at different characteristics of the designed blade.

Keywords

• bem method
• s809 airfoil
• horizontal axis wind turbine
• tip speed ratio
• chord and twist distribution
• aerodynamic study
• inductions factors