Numerical Simulation Of Turbulent Characteristics And Wind Turbine Output Power Under Different Inflow Conditions

Based on the broad prospects of wind energy utilization in building environment,integration of wind energy and building is favored.Due to the existence of a large number of buildings,the wind environment of the city becomes more and more complex,and the distribution of wind field around the buildings is unique.Therefore,for the rational use of wind energy in architectural environment,guarantee the output characteristics of roof wind machine and invisible safety,explore the changes of different inflow turbulence characteristics of roof and roof construction under the condition of the characteristics of wind power,wind turbine to determine the optimal location and height and wind turbine layout,has important significance install the promotion of city building wind energy and wind turbine roof,also has a certain theoretical and practical value.On the basis of the three typical terrain fitting of the corresponding inlet wind profile as the inflow condition,the turbulent characteristics and distribution law of the roof under different inflow conditions are qualitatively and quantitatively analyzed from the point of view of turbulence intensity and wind acceleration factor.The study found that: the index of wind profile corresponding to the outskirts of the city into the flow separation zone is large,the wind acceleration effect of minimum installation height should be more than 0.3 times the height of the building of wind turbine,location for the roof or along the frontier near point.The logarithmic wind profile corresponding to city buildings but no tall buildings of the same height,flow,minimum speed block level generated by the wind acceleration effect is most obvious,but the roof in the rear there are high turbulence zone,roof wind machine should be installed in the height of more than 0.2~0.34 times the height of the building in front of or near the edge point.The wind profile corresponding to the city urban semi log high buildings with the inflow,separation area is minimum,the speed of rapid recovery,building wind acceleration effect is relatively large,and the roof above the turbulent degree is smaller,the wind turbine should be installed in more than 0.15 times the height of the building in front of or near the edge point.Based on the particularity of the roof flow field,put forward the concept of "the top air height,the more prominent characteristics of t high turbulence and low wind speed,focuses on the analysis of the effect of wind speed on the top of the building size air height,provide a theoretical basis for the installation height of roof wind machine.The results show that the height of the top flow decreases gradually with the increase of wind speed,and decreases with the increase of the height of the building.Therefore,the installation height of the roof wind turbine should be considered on the basis of considering the inflow conditions,and the size of the building and the prevailing wind speed in the area should be considered.According to the prediction of the installation height of the roof wind turbine,the wind turbine is installed at a specific location,and the flow field characteristics of the wind turbine and the relationship between the variation of the wind turbine power and the inflow are analyzed.The results show that: in the wake of the wind turbine,there is a clear axial velocity loss region,and the wind turbine wake has different degrees of skewness,the degree of divergence under different inflow conditions is positively correlated with the scope and size of the separation zone.With the increase of the tip speed ratio,the power of the wind wheel increases first and then decreases,and reaches the maximum at rated operating conditions.Due to the acceleration effect of the building wind,the wind speed at the height of the wind turbine is higher than the rated wind speed of the wind turbine under the three inflow conditions.Therefore,the output power of the wind wheel is greater than the rated value.the effect of wind collection is obvious under the condition of logarithmic inflow.The wind speed at the hub of the wind wheel is larger than that of the other two kinds of inflow.Based on the relationship between the size and the height of the turbulence intensity,the wind turbine is installed in the radius of the wind turbine's radius of the wind turbine.The results show that the wind power growth rate decreases with the increase of installation height.Therefore,the safety and installation costs can be increased within the appropriate range of installation height,but the increase should not be too large,about the wind wheel radius(R=0.7m).The above results and theories are of great significance to the construction of wind energy utilization and the installation and promotion of roof wind turbines.