基于冷却幅高的间接空冷塔冷却特性分析与评价

自然通风间接空冷塔的冷却性能直接关系到机组运行的经济性和安全性,为了更加直观、全面地描述空冷塔运行状态和冷却性能,针对某1 000 MW机组间接空冷系统,提出空冷塔冷却幅高的概念,建立理论计算模型,结合现场实测和机组运行数据,研究了环境条件及机组运行参数对冷却幅高的影响规律,通过对比实测冷却幅高与实测工况参数无风条件下冷却幅高计算值,分析了环境风对间接空冷塔冷却性能的影响。结果表明:冷却幅高随环境温度的升高而减小,随进水温度的升高而增大;环境风条件下,主导风向迎风面扇区的冷却幅高低于侧风面扇区。研究结果可为间接空冷系统防冻运行调控、空冷散热器管束清洗和间接空冷塔冷却性能的评价和改善提供依据。

Analysis and Evaluation of Cooling Characteristics of Natural Draft Dry Cooling Tower Based on the Cooling Approach

The cooling performance of natural draft dry cooling tower(NDDCT) is directly related to the economy and safety of the power-generating units. To describe the running status and cooling performance of NDDCT more intuitively and comprehensively, based on an indirect dry cooling system for one 1 000 MW unit, the cooling approach of dry cooling tower is introduced and a theoretical calculation model was proposed. With the combination of field measurement and unit operation data, the influence of environment meteorological conditions and operation parameters on the cooling approach was studied, and the effect of ambient crosswind on the cooling performance of NDDCT was analyzed by comparing the measured cooling approach and the calculated cooling approach under the tested working conditions without crosswind. Results show that the cooling approach decreases with the increase of ambient temperature and increases with the increase of inlet water temperature. Under ambient crosswind conditions, the windward sector cooling approach at the dominant wind direction is lower than that cooling sector at tower lateral. This study could provide good basis for the anti-freezing operational regulation of NDDCT, the radiator bundle cleaning and the cooling performance evaluation and improvements for NDDCT.