| Energy is an important material basis for social and economic development, but with the rapid growth of the national economy, energy consumption becomes increasingly prominent. Wind energy has great potential for development because it is non-polluting and renewable. Development of wind energy has become an important measure to solve energy problems and to achieve sustainable social and economic development. Though the wind power industry develops very quickly, the wind power technology is not mature, new methods are proven. Simulation study of wind turbine aerodynamic characteristics with the method of computer technology combined with aerodynamic theory is very important for further understanding the working principle of wind turbine, is very helpful to solve the problems of the wind turbine during operation, is very meaningful to design and develop new equipments.One of the most effective ways to study wind turbine fluid problems is FLUENT which is based on computational fluid dynamics method. But recent study on the aerodynamic characteristics of wind turbine by FLUENT is almost concentrated in the shape optimization of two-dimensional airfoil. The analysis of whole flow field is limited to the condition of constant wind. Multiple coordinate system method can’t be used to calculate the flow characteristics and aerodynamic loads data which change with the time and space. So there is still a lot of work to do in this area.The object of this paper is1.5MW standard-level wind turbine. In order to study the aerodynamic characteristics of wind turbine, a three-dimensional wind turbine flow field model was established, the motion characteristics of the rotating region and the blade internal were set and the method of sliding mesh was used. Vertical velocity shear wind, gust wind and extreme direction changing wind are three representative wind conditions in wind turbine design requirements. In order to accurately describe the three wind conditions above, the method of User-Defined Function was used. By comparing the simulation results, the UDF method was proved to be feasible and accurate. In order to determine the convergence of the flow field, the residuals were monitored, the monitor of the wind wheel torque coefficient curve was set, the flows of the inlet and outlet was calculated, the unification of the data on the interlace of the rotating and stationary region was judged. In order to prove the accuracy of the FLUENT method, power curves of eight conditions of constant wind were simulated and the error was around16percents. Error became10.8percents when the simulation step size was reduced to0.002s, so the step size has a major impact on the simulation results. The average wind speed at the height of hub was set to10m/s. The simulation under the condition of vertical velocity shear wind and gust wind was done. Characteristics of the pressure and velocity around the blade were analyzed. Action principle of the airflow and the blade was discussed combining with the blade element theory. Aerodynamic loads over time were recorded. The wind turbine output power of vertical velocity shear wind condition was calculated,1.09MW reaches81.5%of the standard value. Fluctuations of the torque and power curve were specified and the negative impact of the tower shadow effect was described qualitatively.Aerodynamic characteristic of the1.5MW wind turbine was studied in this paper. The operating conditions are typical wind conditions specified in the wind turbine design requirements. New attempts on the wind speed modeling and load simulation method were made. Load data and other simulation results can lay the foundation for the dynamic simulation. The simulation method in this paper can provide a reference to simulation study on wind turbine. |
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