空气冷却塔自然对流的数值研究

对于海勒式空冷塔在设计工况下因热交换而引起的自然对流现象,以及环境大气温度对空冷塔自然对流和热交换影响问题进行了数值研究.研究中,我们采用了非交错网格的有限体积方法求解包含浮力作用的雷诺平均Navier-Stokes方程,其中浮力项的处理采用联系密度和温度变化的Boussinesq近似.通过计算我们得到了空气流量和散热量与正比于Grashof数的温度无量纲量的关系,与一些实测数据十分吻合,可为优化设计参数、研究自然风的影响提供理论基础.

Numerical Study of Natural Convection of Natural Draft Dry-cooling Tower

The paper provides preliminary finding of the aerodynamic characteristics on a natural draft dry-cooling tower. Particular attention has been focused on the numerical study of natural convection, induced by heat exchange, inside the cooling tower under the designed working conditions. In the solution procedure, the Reynolds-averaged Navier-Stokes equation, which includes buoyancy force, is solved with finite-volume method on a non-staggered grid. The introduction of the buoyancy force in the Navier-Stokes equation is through the Boussinesq approxi- mation which relates the density variation to temperature in a linear manner. The present study illustrates that the performance of the cooling tower system, i. e. the volume flow rate, heat transfer rate, is closely related to atmospheric temperature as observed in practice. It is also established that the volume flow rate and the heat transfer rate exhibit linear relation with a nondimensional temperature parameter (which is proportional to Grashof number). This finding has great practical significance for cooling tower design as well as power station management.