冷却空气迎面风速和温度对直接空冷系统动态特性的影响

Influences of Cooling Air Face Velocity and Temperature on Dynamic Characteristics of Direct Air-cooled System

直接空冷机组和常规湿冷机组由于在冷端系统上差别较大,使得空冷机组的控制必须考虑外部环境变化对于汽轮机冷端的影响。该文在空冷凝汽器静态变工况计算的基础上,考虑空冷系统凝汽器的蓄热效应,建立了直接空冷凝汽器动态数学模型,该模型能够分析冷却空气迎面风速和环境温度对直接空冷系统凝汽器动态特性的影响。得到了冷却空气迎面风速和环境温度对直接空冷机组背压的影响曲线,仿真结果表明随着环境温度的升高和冷却空气迎面风速的降低,系统的稳定时间变长,证明直接空冷系统凝汽器的时间常数随着空冷凝汽器的散热能力的强弱而有相应变化,并为进一步研究适用于直接空冷机组的背压保护控制策略提供了参考。

Due to the difference in cooling systems between direct air-cooled units and normal units, the influence of environmental variation on turbine cooling system control should be taken into consideration. Considering the thermal storage effects of air-cooled condensers, a direct air-cooled dynamic condenser model was developed based on the static off-design performance. The influences of cooling air face velocity and temperature on the condenser dynamic characteristics were analyzed. And the back pressure response curve with the cooling air face velocity and temperature is presented. The simulation result shows that the stabilization time becomes longer if the ambient temperature gets higher or the cooling air face velocity is lower. Moreover, it proves that the time constant of the direct air-cooled condenser varies with the heat-sinking capacity of the air-cooled condenser. This result is useful for the research on back pressure protection control method of air-cooled units.