摘要
无论直接还是间接空冷系统,其热力性能都受到环境气象条件的显著影响。研究不同环境条件,不同机组热负荷和操作条件下机组背压的变化规律,对于电站空冷系统变工况优化运行具有重要参考价值。该文建立了电站空冷系统变工况运行性能的计算模型和数值方法,分别以典型直冷和间冷系统为例,通过数值模拟,获得了不同环境气象条件下,直冷系统空冷凝汽器空气流量和进口空气温度,以及间冷系统空冷散热器空气流量和进口空气温度。以变工况数值计算为基础,分析了直接和间接空冷机组背压的变化规律。结果表明,直接空冷系统热力性能随风速和风向发生显著变化,并随风速增加而降低,导致机组背压随风速增加而升高。对于间接空冷系统,其热力性能先随风速增加而降低,随后又增加,使机组背压呈现先升后降的变化趋势。电站空冷系统变工况性能的数值研究结果,可用于指导空冷系统的优化设计和安全运行。
The thermo-flow characteristics of direct and indirect dry cooling systems are both influenced by the ambient conditions conspicuously.It is of benefit to the optimal off-design operation of the dry cooling system in a power plant to investigate the variation of the back pressure with various ambient conditions,heat load and operating status of the generating unit.On the basis of the representative direct and indirect dry cooling systems,the computational models and numerical methods for the off-design performances are developed.The air flow rate and inlet temperature of air-cooled condensers for direct dry cooling system,and those of air-cooled heat exchangers for indirect dry cooling system at various ambient conditions are obtained by numerical simulations.The back pressures of both the direct and indirect dry cooling generating units are calculated and analyzed in terms of the off-design numerical approach.The results show that the thermo-flow performances of direct dry cooling system vary widely with the wind speed and direction,and become deteriorated with increasing the wind speed,resulting in the increased back pressure of the generating unit.For indirect dry cooling system however,the thermo-flow performances are primarily worsened,then become improved as the wind speed increases.The back pressure increases at first and then decreases with increasing wind speed accordingly.The numerical approach to the off-design performance can be used to the optimal design and operation of direct or indirect dry cooling system in power plants.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2012年第35期66-73,共8页
Proceedings of the CSEE
基金
国家重点基础研究发展计划项目(973计划)(2009CB219804)
国家科技支撑计划项目(2011BAA04B02)~~
关键词
电站空冷系统
空冷凝汽器
空冷散热器
流动传热性能
背压
dry cooling system in power plants
air-cooled condenser
air-cooled heat exchanger
flow and heat transfer characteristics
back pressure
