超大型阵列光伏板体型系数遮挡效应研究

在我国新能源战略的大背景下，光伏发电得到快速发展，超大型光伏工程的光伏阵列可达数十列数十排。采用风洞试验和CFD数值模拟相结合的方法研究超大型阵列光伏板体型系数及群体遮挡效应。试验模型在风洞宽度方向满布，以实现大型阵列光伏板的二维绕流。采用大比例刚性模型上下表面同步测压技术确定倾角为12°时串列5片光伏板的风压系数分布、体型系数和遮挡效应，同时采用CFD的realizable k-ε湍流模型进行计算，与试验结果比对验证了计算方法的有效性。在此基础上，对串列16、24、32片光伏板进行CFD数值模拟，研究不同倾角及不同串列数对光伏板体型系数的影响，并给出了超大型阵列光伏板体型系数随光伏板串列数的变化规律。结果表明：倾角为20°时的遮挡效应明显大于倾角为12°时的遮挡效应,遮挡效应随着上游光伏板数量的增加而增大，当上游光伏板数量达到12片以上时，遮挡效应趋于稳定。结合试验和CFD模拟结果，将超大型光伏阵列分为边缘区、渐变区和稳定区，并给出各区体型系数取值建议。

Study of shielding effect on shape coefficient of super-large photovoltaic arrays

Under the background of China’s new energy strategy, photovoltaic power generation has been extensively developed, and the photovoltaic array of super-large photovoltaic projects can reach dozens of rows and dozens of columns. The wind tunnel tests and CFD numerical simulation were adopted to study the shape coefficient and the shielding effect of super-large PV arrays. To simulate the two-dimensional flow in the wind tunnel, this research set the models of PV arrays fully along with the width of the wind tunnel. The wind pressure distribution, shape coefficient, and shielding effect of a 5-panel PV row with a tilt angle of 12° were investigated by carrying out synchronous pressure measurement technique on a large-scale model of PV arrays. In addition, CFD simulations were conducted on the PV arrays based on realizable k-ε turbulence model, and the simulation results were compared with the experimental results to verify the effectiveness of the simulation method. Subsequently, the turbulence model was adopted to simulate the shape coefficients of PV rows with 16, 24, and 32 panels, respectively. The variation of PV shape coefficients with tilt angles and panel numbers was studied. The results show that the existence of upstream PV panels has a significant shielding effect on the downstream PV panels, and the shielding effect at a tilt angle of 20° is greater than that at a tilt angle of 12°. The shielding effects enhance as the increase of upstream PV panel. When the number of upstream PV panels exceeds 12, the shielding effect becomes stable. Based on the experimental and simulation results, recommendations for wind load shape coefficient and corresponding reduction factor for the side zone, the gradient zone and the stable zone of super-large PV arrays were proposed.