Research On Flow Field Driving Mechanism And Aerodynamic Model Of 10MW Wind Turbine Based On PIV Test

In order to obtain a higher utilization rate of wind energy,the overall structure of the wind turbine has been developed in the direction of extra large flexible blades and ultra-high slender towers.The stiffness and natural frequency of the wind turbine system have been reduced,making the extra large wind turbine system more sensitive to the effects of wind loads.Many current research objects on wind turbine resistance to strong wind are small and medium-sized models.With the development of wind turbines,the complex wind environment and three-dimensional rotating unsteady flow will bring a huge challenge to accurate prediction of aerodynamic loads,coupled with wind turbine tail vortices.Multi-scale superposition and mutual interference,the dynamic development and evolution mechanism of the wake is not clear,and the practical problems of conventional aerodynamic calculation theoretical models and engineering experience are no longer applicable.Therefore,summarizing the aerodynamic distribution law of the entire 10 MW super large wind turbine,discussing the flow field driving,development and evolution laws,and performing 3D wind load and wind-induced dynamic calculations are of great theoretical significance and engineering application value.In view of this,this article uses a 10 MW wind turbine independently developed by Nanjing University of Aeronautics and Astronautics as the engineering background.The PIV(Particle Image Velocimetry)test is used to study the flow field development and vortex shedding of a typical cross section of the wind turbine.The wind power is compared and analyzed with numerical simulation results.The aerodynamic distribution characteristics of the wind turbine system under different stop positions,yaw angles and pitch angles.Based on the most unfavorable load distribution model,the wind-induced dynamic calculation is performed,and a 10 MW class wind turbine in a good state(type A)wind farm is discussed The dynamic characteristics of the system and the distribution law of wind vibration coefficients reveal the mechanism of aerodynamic interference of 10 MW super large wind turbine structures.This article has carried out the following four aspects of work:1.PIV test and flow field observation: Based on the PIV test principle,the technical parameters and test procedures of the test wind tunnel and test model are introduced in detail.The 10 MW super large wind turbines are studied from the perspective of real shot maps and velocity streamlines.Stream characteristics.2.Numerical simulation of CFD(Computational Fluid Dynamics)and analysis of flow field characteristics: The large eddy simulation method is used to carry out numerical simulation of the wind turbine good state(type A)wind field at different stopping positions,yaw angles and pitch angles.The average wind pressure cloud diagram,vorticity distribution and velocity streamline are used to analyze the wind field characteristics and aerodynamic distribution of wind turbines under different working conditions.3.Research on aerodynamic distribution under complex working conditions: consider the average wind pressure,lift / resistance coefficient,and pulsating wind pressure characteristics of wind turbines under different working conditions in consideration of the stopping position,yaw angle,and pitch angle,based on the overall resistance coefficient of the tower Obtain the most unfavorable aerodynamic distribution conditions.4.Wind-induced response analysis: The wind-induced dynamics calculation of the wind turbine system under the most unfavorable working conditions is performed using the full transient method.Based on different equivalent targets,the criteria for the tower and blade wind vibration coefficients are explored to refine the good state(type A)wind.Dynamic characteristics of wind turbine system under field and the distribution law of wind vibration coefficient.Finally,the main research results of this paper are summarized: PIV test can be used as an effective means to observe the development,evolution and evolution of the flow field.The flow field characteristics,wind pressure distribution and pulsation characteristics of wind turbines are different under different working conditions.Taking the overall drag coefficient of the tower as an equivalent target,the aerodynamic performance of a 10 MW super large wind turbine is most disadvantageous at15 °,the most disadvantageous yaw angle is 0 °,and the most disadvantageous pitch angle is 80 °.Based on the most unfavorable wind pressure distribution model for wind vibration analysis,the wind node vibration coefficient distribution of the tower node under the equivalent target R-P is the most reasonable;the wind vibration coefficient distribution of each blade is different along the span direction.The relevant conclusions can provide a reference for the design of strong wind resistance of large wind turbine systems.