Study On Design Wind Load Of Photovoltaic Power Station With Low Building Slanted Roof

Wind load is the main external load borne by photovoltaic array system,and the damage and vibration of photovoltaic panels are mainly caused by wind load.Wind load on photovoltaic panels is controlled by many factors.In this paper,the accuracy of numerical simulation is verified by comparing wind tunnel test with numerical simulation.Finally,the influences of dip Angle,wind Angle,weir length,gable height,voidage and other factors on wind load characteristics of photovoltaic panels are studied through a large number of numerical simulation.The results show that:In the wind tunnel experiment,the roof dip Angle is set to 30°.When the wind direction Angle is 0°～90°,the body shape coefficients of the windward front are all negative.With the rotation of the wind direction,the positive pressure area gradually decreases,while the negative pressure area shifts to the angular area with the wind direction.When the inclination α=5°,10°,15°,the wind load on the photovoltaic panel is controlled by the airflow reflux.When the tilt Angle α=20°,25°,there is eddy current above the photovoltaic panel;When the inclination Angle α=30°,40°,55°,the air flow basically did not separate,the whole plate presented downward pressure.At 180° wind Angle,the backflow of the air flow has a great influence on the photovoltaic panel.The backflow generated at a low Angle causes negative pressure on the photovoltaic panel,while the backflow generated at a high Angle causes positive pressure on the photovoltaic panel.When the wind direction is downwind,the roof tilt Angle α is less than or equal to20°,and the body shape coefficient of the PV panel surface is negative.When the roof tilt Angle α is greater than 20°,the surface shape coefficients of PV panels are all positive.After the merger,the body size coefficient of the whole was positive in the downwind direction,and showed a trend of increasing first and then decreasing.When the wind direction is upwind,no matter the upper surface,lower surface or the combined whole,the body shape coefficient fluctuates around 0.Through the comparison between the numerical simulation and the design specifications of various countries,the Chinese specifications are more referential when the positive pressure is applied.When the PV panels are subjected to negative pressure,the specifications of the three countries are relatively conservative,and the upper and lower surfaces in the numerical simulation data are separated and compared with the specifications,but the overall body size coefficient of the numerical simulation is smaller than that of the specifications.When the wind direction is 0° and the length of weir is 0m,the larger the dip Angle is,the larger the body size coefficient of PV panel is.When the Angle is less than 30°,the body shape coefficient increases with the increase of the length of the cornice.When the Angle is greater than or equal to 30°,the body shape coefficient decreases with the increase of the length of the cornice.When the dip Angle is greater than or equal to 30°,the body size coefficient of photovoltaic panels is mostly positive.Because of the shielding of the roof ridge,the change in the length of the cornice has little effect on the wind load of the photovoltaic panels on the roof.Without the gable,the body size coefficient of the roof photovoltaic panel is basically the largest.After increasing the setting of the gable on both sides and the surrounding gable,the body size coefficient of the photovoltaic panel has significantly decreased.The installation of gable wall will significantly reduce the wind load of photovoltaic panel,but in the upwind direction,the presence of gable wall has little effect on the wind load of photovoltaic panel.The higher the gable wall is,the more obvious the wind load on the photovoltaic panel will be weakened.Under the closed condition,there is no gap between the photovoltaic panel and the roof,and the air flow quickly passes through the upper surface of the photovoltaic panel,resulting in reduced pressure,which makes the photovoltaic panel bear the pulling force,and the body shape coefficient is negative under different wind direction angles.After increasing the void,the air flow accelerates through the void,resulting in the wind suction on the lower surface being greater than that on the upper surface,making the photovoltaic panel bear the downward pressure,and the body shape coefficient reaches the maximum when the void ΔS=0.05 m.When voids exist,contour maps of body shape coefficient of upper surface of roof and lower surface of PV panel are basically the same.Therefore,in the numerical simulation calculation,only the data extraction points are set on the upper surface of the roof and the lower surface of the photovoltaic panel,and then the general distribution law of the size coefficient of the entire photovoltaic panel can be obtained.Figue[77] table[17] reference[65]...