风-雨共同作用特大型冷却塔表面风荷载与作用机理

强风暴雨极端气候条件下,暴雨会直接影响塔筒表面气动力并改变脉动风的湍流特性,而传统研究大多仅关注风单向驱动雨对于结构表面的冲击力.为解决该问题,针对中国已建成的高为210.0 m的超大型冷却塔,首先基于计算流体动力学(computational fluid dynamics,CFD)手段采用连续相和离散相模型分别展开风、雨场的模拟计算.在此基础上,揭示风雨场雨滴运行速度和轨迹的作用机理,并针对9种不同风速和降雨强度组合的塔筒内、外表面风雨荷载,雨压以及等效压力系数等展开定性和定量的对比分析.提出的超大型冷却塔风雨等效内、外压系数可以很好地预测此类极端条件下的表面荷载取值.

Surface Wind Load and Action Mechanism for Super Large Cooling Towers Under Simultaneous Actions of Wind Rain

Under extreme weather conditions with strong wind and rainstorm, the rainstorm will directly affect the aerodynamic force on the cooling tower surface, and change the turbulent characteristics of fluctuating wind. However, most traditional researches have only paid attention to the impact force characteristics of wind driven rain on structural surface. In order to solve this problem, aiming at the 210 m world tallest cooling tower in China, the wind field and rain field are simulated respectively by using the continuous model and the discrete phase model based on the computational fluid dynamics (CFD) method, based on which, the action mechanism of the moving speed and trajectory of rain drops in the wind and rain fields are revealed. Besides, the qualitative and quantitative analysis of wind loads, rain loads, rain induced pressure, and equivalent pressure coefficient of 9 different combinations of wind speed and rain intensity are conducted. The surface loads of cooling tower under such extreme conditions can be well predicted based on the equivalent pressure coefficient proposed in this paper.