Coupled Aerodynamic Design Method for Counter-Rotating Wind Turbine

The relationship between power and axial velocity induced factors of front and rear grades for identical radius counter-rotating wind turbines(CRWTs)was derived based on blade element momentum theory. The results were in good agreement with the classical model. The Wilson design method for single grade wind turbine was developed into design method of CRWTs considering flow interference between both turbines. The optimal design was based on achieving maximum power coefficient of the annular disc, and axial and annular induced factors for front and rear grades as the variables. 2 kW single grade wind turbine and CRWT were designed. Finally, the CFD method was used to validate the experimental results and the design results of CRWTs. Numerical calculation results show that the power coefficient of the designed CRWT(46.32%)is higher than that of single grade wind turbine(41.44%). The difference between the numerical prediction of wind energy utilization rate(64.00%)and theoretical optimum value(59.26%)was analyzed.