Numerical And Experimental Research Of Wind Turbine Wake Accelerated Region Of Based On Actuator Disc Model

The exponential acceleration of the wind power sector in recent years has significantly decreased the feasible areas for additional wind turbines on land and on the sea.Wind farm layout studies have become more important in suggesting ways to improve the utilization rate of wind resources and the economic design of wind farms.Under specific atmospheric conditions,a reasonable wind farm layout can make use of wind energy more effectively,reduce construction costs and improve the stable output of wind farms.This study mainly considers wind turbines are arranged side by side,the wake decay and acceleration regions between the wind turbines,additionally,the regions with surplus wind speeds in comparison to freestream.The side-by-side arrangement of wind turbines allows for optimal utilization of wind resources.The numerical and experimental analysis(on the wind tunnel)for the wind flow regions was carried out as follows:1.The characteristics of the velocity deficit and acceleration region in the wake region of a single wind turbine are estimated.The steady-state computational fluid dynamics(CFD)equation,k-e turbulence model,and UDF were used to simulate the drag effect of the wind turbine on the airflow,and the wake and acceleration region of a single wind turbine is numerically analyzed.The different flow settings were obtained by adjusting the axial velocity induction factor.A comparison of the experimental and numerical wake wind speed profiles shows that this experimental method can more accurate in estimating the deficit zone and acceleration zone in the wake.2.The wake profiles for a scaled wind turbine model were measured in a wind tunnel while maintaining a stable wind speed.The velocity distribution of two sections in the wake was measured by changing the position of the wake and axial direction.According to the wake deficit in the experiment,the axial velocity induction factor is calculated.For comparison purposes,this study considered the same axial velocity induction factor for the calculations.3.The side-by-side comparison of the flow characteristics and the wind speed between two wind turbines considering considered the axial velocity induction factor of0.3 and the corresponding thrust coefficient of 0.8.This study’s computational domain is based on a turbine spacing of 2D,3D,4D,and 5D.The analysis and comparison of the flow characteristics show that when the wind turbine spacing is 3D,the wind power density in the wake acceleration region increases by about 13.62%.4.The influence of the atmospheric boundary layer on the acceleration region was also considered.At the inlet,measurements are set as the velocity profile of the atmospheric boundary layer.The same conditions were assumed for the simulations.The flow field of two wind turbines is arranged side-by-side with the spacing of 3D,4D,5D,and 6D.The wake profiles were estimated at the different downstream positions.The results at 3D spacing show an increase in the wind power density in the wake acceleration region at 13.2% due to the influence of the atmospheric boundary layer.This result suggests that the existence of an atmospheric boundary layer reduces the wake decay effect.This study estimates and validates the performance of the wind farm layouts with a staggered arrangement and or mixed arrangement.The first wind turbine row was arranged in a compact space,and therefore a wind acceleration region can be seen in the downstream region,with 1.1 times more output.Because of the time relationship,this part of the calculation work is only viable for this arrangement,without in-depth multi-parameter comparison and research.For some regions where the main wind direction is particularly stable,compared with the conventional(equidistant)regular array arrangement,this kind of staggered layout may have higher utilization of wind energy,and a more viable option compared to the conventional layout.In the future,more accurate wake models or experiments can be used to further study the stability of wind direction and the advantages and disadvantages of broken line/array arrangement.