Research On Impact Effect Of Cas-solid Two-phase Flow And Soil Mechanical Composition To Photovoltaic Power Station

The dissertation takes the photovoltaic power station of Wuhai city,Inner Mongolia as the research object,observes the multi-point wind velocity,sand transport rate and mechanical composition of soil of the surface and analyses the distribution of gas-solid two-phase flow in the photovoltaic power station through field observation and indoor wind tunnel simulation test,in order to investigate the differentiation of wind variation and configuration parametric variation to wind-sand flow field distribution,which aims at understanding the feedback mechanism of environmental factors towards the setting up of the photovoltaic power station and providing theoretical foundation to keep the photovoltaic power station from being attacked by the wind-sand damage.The results shows that:(1)The wind velocity at different part of the photovoltaic panels shows,it performs"S" as the height increases in the front eaves,the back eaves of photovoltaic panels.While the wind velocity accelerates and then decelerates underneath the panels;The sand transport rate of the matrix decreases as the height increases in the front eaves,the back eaves and underneath the photovoltaic panels.The optimal fitting equation of sedimenttransport rate at each observation point are polynomial functions.The R2 of the fitting equation is greater than 0.86;through analyzing the characteristic value of wind-sand flow at different points,the value of front eaves,back eaves of the photovoltaic panels is greater than 1,which means the wind-sand flow is affected by the inclination of photovoltaic panels and forms an airflow acceleration zone,which results in enhancing the sand carrying capacity.The wind-sand flow appears to be unsaturated,and the earth surface is eroded.So the focus of the sand control work is at the underneath area of the photovoltaic panels;The mechanical composition of soil in the front eaves of photovoltaic panel shows soil coarse graining first then shows opposite impact,the volume percentage content of very fine and fine sand tends to increase while that of the medium grained sand and coarse sand decreased in comparison to the contrast observation points in the back eaves of photovoltaic panel and under boards of photovoltaic panel.(2)Wind velocity in each sample line performs "J" as the height increases in different location of the track of the photovoltaic matrix.As a whole,the passage wind weakens as it passing through the photovoltaic matrix,field contrast observation point,and each observation points.The downwind velocity in 250cm reduced 66.99%,compared with that of the contrast observation point.In other words,the photovoltaic matrix significantly reduces the wind velocity.The analyzing results of wind velocity variance show that,photovoltaic panels are the main reason for wind velocity variance in different location;The characteristic values of wind-sand flow structure at the track of the photovoltaic matrix is less than 1.It is because photovoltaic panels have blocking effect to the upwind sand flow,so that the wind sand flow is saturated and the earth surface is up heaped.Compression to the sand transport rate at each observation point in different location shows that,the sand transport rate is different around and in photovoltaic matrix.The sand transport rate decreased as the sand flows deeper into its.It can decrease 93.42%at the most.This means that the photovoltaic matrix has controlling effect to the wind sand transport.Therefore,the key position of the photovoltaic power station in the sand area to control the wind erosion and sand damage is at the upwind direction;The statistical result of the mechanical composition of soil in the track of the photovoltaic matrix shows that soil coarse graining first then shows opposite impact;The amplitude of the silt and the coarse sand in the photovoltaic matrix is relatively large.Each grades of the soil particle range from7.53cm to 25.58cm,with good continuity.The result of mechanical composition of soil variance analysis shows that photovoltaic panel is the main reason for soil particle composition variance in the different locations.(3)The analyzing result of the passage wind effect in different seasons shows that,the average decline wind velocity at the downwind observation point of the photovoltaic matrix is summer>winter>autumn>spring,means that the average wind velocity in the summer and winter is small and decreases significantly when the passage wind passing through the photovoltaic matrix.While,in spring and autumn,the result is opposite.Therefore,spring and autumn are the key periods for controlling the wind-sand transport.(4)Simulation test of wind field and photovoltaic power station preventing the wind sand transport shows that,the sand transport rate of the array model is proportional to the wind velocity.There are differences in sand transport rate and wind-sand flow in 0-50cm sand height due to the wind direction.When the wind velocity is fixed,the sand transport rate of the array is the highest when it is the south wind,which is 65.41%and 70.23%higher than when it is northwest wind and northeast wind respectively;When the wind tunnel model is reduced by equal proportion and the line space is 20cm,the sand transport rate of the matrix becomes the highest.It is 74.42%higher than when it is 18cm and 58.49%higher than when it is 22cm.The straw sand barrier can be set up on the upwind direction of the photovoltaic matrix,which can reduced the sand transport rate by 66.67%.That means,to set up send barrier against the wind on the edge of the photovoltaic power station can reduce the sand wind transportation effectively.It plays an important role in sand control of photovoltaic power station in sand area.