最新中英整理内陆核电厂用水系统冷却塔空气动力特性数值模拟研究1

中英整理内陆核电厂用水系统冷却塔空气动力特性数值模拟研

究1

鼓风式机械通风冷却塔空气动力特性数值模拟研究

赵顺安、李红莉、毋飞翔

（中国水利水电科学研究院，北京100038）

Numerical research on aerodynamic characteristics of the forced draft

mechanical cooling tower

Zhao Shunan、Li Hongli、Wu Feixiang

(China Institute of Water Resource and Hydropower Research, Beijing 100038 )

摘要：鼓风式机械通风冷却塔常用于核电厂的重要厂用水系统，但相关设计规范并没有给出冷却塔的空气动力特性计算公式。本文采用Fluent软件对鼓风式机械通风冷却塔的空气动力进行了数值模拟计算，对冷却塔的设计布置进行了优化，分析总结给出了冷却塔阻力计算公式。结果表明，填料安装位置对鼓风式机械通风冷却塔整塔阻力影响不大，但会影响填料断面风速分布均匀性，填料安装高度越低，风速分布越均匀；出口收缩段的高度越高，整塔阻力越小，风速分布越均匀；出口收缩段与水平的夹角越大，整塔阻力系数越小，但变化趋势不明显，收缩角基本不影响填料断面风速分布均匀性。

关键词：鼓风式冷却塔；塔型；阻力系数；风速均匀性

Abstract:The forced draft mechanical cooling tower is always used in a nuclear power plant, while the relevant design specifications have not formula about the aerodynamic characteristics of cooling tower. This paper uses FLUENT software to simulate and study the aerodynamic characteristics of the forced draft mechanical cooling tower, and optimize the design of the cooling tower, and analysis to summarize the cooling tower resistance calculative formula. The results show that the height of the fill has little effects on the whole tower resistance coefficient, but it influences the wind velocity distribution uniformity of the fill section, the lower the position is, the more uniform the wind velocity distribution is; the convergent section height is higher, the whole tower resistance is smaller and the wind velocity distribution is more uniform. The angle between convergent section and horizon is bigger, the whole tower resistance is smaller, while this trend is not obvious, it does not affect the wind velocity distribution uniformity on the fill section. Keywords:the forced draft mechanical cooling tower, tower shape, resistance coefficient, wind velocity distribution uniformity

1研究背景

内陆核电厂的重要厂用水的水量不大，但却影响核电厂的安全。鼓风式机械通风冷却塔能较好地适应核电对安全性和抗震性能的要求而常被内陆核电厂采用。

鼓风式机械通风冷却塔不仅在通风方式上有别于常规的抽风式机械通风冷却塔，在塔型结构布置上也有明显差异。我国的相关设计规范和资料对鼓风式机械通风冷却塔没有明确的设计计算方法[1～5]。为了解塔内气流特性并对塔型进行优化，需要通过相关的研究来确定其空气动力特性。通过物理模型试验来研究冷却塔空气动力特性是一个十分有效的手段，但是由于鼓风式机械通风冷却塔模型本身的复杂性及系统试验的塔型的变化，使模型试验研究工作量和投资都很大。

本文利用Fluent软件建立鼓风式机械通风冷却塔空气动力计算的数学模型，经过与试验结果对比验证，确定模型参数和网格数量。研究了不同塔型条件下塔内气流分布及阻力特性，最终分析总结出了鼓风式机械通风冷却塔的阻力计算公式以及塔型与配风均匀性的关系。阻力系数计算公式与试验结果相比偏差小于5%，可为设计提供参考。

1research background

The water quantity of important water system of inland nuclear power plant is not big, but it affects the security of nuclear power plant. The forced draft mechanical cooling tower can satisfy the requirements of equipment security and earthquake resistance, so it will be used more and more in inland nuclear power plant.

The forced draft mechanical cooling tower is not only different from the conventional induced draft mechanical cooling tower in ventilation way, but also has distinct difference in tower shape and structure layout. China's relevant design specifications and information on the forced draft mechanical cooling tower have no clear design method. For understanding the airflow characteristics of the tower and optimizing the tower shape, it's necessary to do some relevant research to realize the aerodynamic characteristics. It's a very effective way to establish a physical model to study the aerodynamic characteristics of the cooling tower, however, due to the forced draft mechanical cooling tower model's complexity and variability, the workload of experiment and investment is very big.

This paper uses FLUENT software to build a mathematical model of the forced draft mechanical cooling tower to study the tower aerodynamic characteristics, and after comparing with the experimental results to determine the model parameters and grid number. It studies the airflow distribution and resistance characteristics in the conditions of different tower shapes, and analysis to summarize the cooling tower resistance calculative formula and the relationship between tower shape and airflow distribution uniformity. The difference of computational resistance coefficient and the experimental results is less than 5%, it can provide a reference for design.