Application Investigations Of Deploying Flow Control Microtab On A Wind Turbine Airfoil

Flow control technique is an important embranchment of aerodynamics, which can remarkably improve aerodynamic performance of flight vehicles. Many control avenues appear with the development of control devices, material science and experiment instruments. Through flow control method to improve the aerodynamic performance of wind turbine is of great importance to the development of wind turbine.The thesis conducts study of the application of microtab flow control method in the wind turbine. Through previous literature study, microtabs have been proposed to be deployed on the pressure surface and near trailing edge of an airfoil. Experimental measurement and numerical simulation are the basic methods of study of internal flow field of turbomachinery.This thesis conducts both experimental measurement and numerical simulation to study the detailed structure of flow field of S809 airfoil and the ones with microtabs. Main contents of this thesis are described as following:1. Builded up experimental test installation suitable for airfoil blowing experiment, to make sure of good flow conditions, good uniformity of velocity and low turbulence. By using advanced flow measurement facility-----Time Resolved Particle Image Velocity, we conducted experimental measurement of base airfoil and the one with microtab.2. Three different airfoils were adopted for experiment, which were the base airfoil, the airfoils with microtabs at 90% and 95% the chord. By changing the attack of angle, obtained the velocity flow field of the three airfoils versus different attack of angles. After data processing, obtained the velocity vector, streamline, and axial velocity, then compared the flow performance of the airfoils with and without microtabs versus different attack of angles. It was found that the presence of the microtab change the stagnation point position at trailing edge, thus change the circulation around the airfoil, resulting in an impact on the lift.3. Using ICEM CFD to perform the grid meshing of the detailed computational meshes of airfoils with and without microtabs, obtained convenient and effective mesh structure. The numerical simulation of base airfoil and airfoil with microtab at 95% of chord were performed on ANSYS CFX software platform, using SST turbulence model suitable for airfoil simulation. 4. After processing of the numerical simulation results, obtained lift coefficient, drag efficient, lift-drag ratio, surface pressure coefficient, and streamline, etc. Analyzed the reason of lift generated by microtab from the prospect of the detailed flow field. The microtab could generate additional lift was because that the presence of microtab change the kutta condition, shift the stagnation point position, which effectively increase aerodynamical camber and circulation, thus enhance the lift.