漂浮式光伏电站方阵环境载荷计算方法研究

针对我国建成的全球首个单体容量达到40 MW的漂浮式光伏电站方阵进行了环境载荷数值预报研究，在与风洞模型试验结果对比验证的基础上，基于计算流体力学（computational fluid dynamics，CFD）方法对该大规模方阵的整体风载荷和流载荷进行了数值研究。CFD计算的数值考察验证了采用简化浮体模型进行研究的可行性，单体模型的计算结果与风洞试验结果吻合良好；对方阵进行实尺度建模及3D简略计算，得到了整体风载荷在不同风向角下的变化规律；通过对最大载荷风向的北风条件下的载荷分布规律的分析，提出了2.5D计算的策略，得到了数值验证；根据计算结果设计并实施了18行×11列单元模块的缩尺方阵风洞试验，试验结果和CFD计算结果吻合良好，据此构建了完整的数值计算方法；对2.5D进行高精度计算，确定了针对3D简略计算的修正系数，得到较为准确的整体风载荷结果。流载荷计算方法与风载荷相同。采取势流计算方法开展了波浪载荷数值分析研究，得到了在单位波幅规则波作用下漂浮方阵波浪载荷随行和列的变化规律；根据此规律获得了整体漂浮方阵的波浪载荷，并据此计算了50年一遇的极端条件下漂浮方阵所受的波浪载荷。该研究为漂浮式光伏电站的风、流、波浪等环境载荷的数值预报提供了方法，为漂浮方阵的锚泊计算及水上光伏电站的系统设计提供了技术支持。

NUMERICAL METHOD STUDY ON ENVIRONMENTAL LOADS OF FLOATING PHOTOVOLTAIC POWER ARRAY

Numerical prediction on environmental loads for the first 40 MW floating photovoltaic power station built in China is carried out.Based on the verification from the comparison with the measured data in a wind tunnel,a CFD(Computational Fluid Dynamics)method is applied to study the wind load and the current load on a large-scale square array.CFD numerical investigation verifies it feasible to adopt a simplified floating body model instead of the original one.The computational results of the model monomer are in a good agreement with the wind tunnel measured data.The 3D full scale square array's simplified calculations based on a coarse grid are carried out,and the distributions of wind loading on the array under various wind direction angles are obtained.Through the analysis of the distribution of maximum wind loading at north wind,the strategy of 2.5D calculation is put forward and numerically verified.According to the computational results,an 18(row)×11(column)scale model array test plan is designed and performed in a wind tunnel.The measured results are in a good agreement with CFD results,thus a global numerical calculation algorithm is set up.The 2.5D calculation based on a fine grid provides correction coefficients to rectify the 3D computational result to obtain more accurate wind loads.The calculation method for current loads is similar to that of wind loads.The numerical computation and analysis on the wave load are performed by the potential flow method.The wave load variations,at regular waves with unit wave amplitude,along the row or the column are obtained.According to the variation,the whole wave load is estimated.The wave load on the array is predicted at the extreme condition of a fifty-year return period.This study provides a method for the numerical prediction of wind loading,current loading and wave loading on a floating photovoltaic power station.The researches provide a technical support for anchoring the calculation of floating square array and the system design of floating photovoltaic power stations.