电站空冷岛轴流风机模型研究

Research on Axial Flow Fan Models of Air Cooling Island in Power Plant

【目的】轴流风机作为直接空冷系统的主要设备,其气动性能对于直接空冷系统的流动换热性能具有重要影响。由于空冷岛的流动换热问题在空间几何上跨越了多个尺度,采用实验方法进行研究较为困难,通常利用数值模拟的手段进行研究。因此,对于现在大多数模拟工作中采用的简化风机集总参数模型(简化模型)的准确性进行讨论分析十分必要。【方法】采用数值模拟的方法,分别建立了包含风机叶片的实体风机模型(实体模型)和简化模型。分别研究了不同温度、风速、风向角条件下采用实体风机和风机模型对于电站冷端系统输运性能的影响规律,通过对比分析获得了各个工况下的空气侧压力场和流场的分布规律,并对采用不同风机模型的电站冷端系统各个空冷凝汽器单位的轴流风机冷却空气压降和流量进行了统计和对比。【结果】实体模型与简化模型的差异主要体现在低流量区,且风速越大,差异越明显。【结论】研究结果可为提高电站冷端系统数值模拟研究的准确性提供参考。

[Objectives]As the main equipment of the dry cooling system,the aerodynamic performances of axial flow fans play an important role in the flow and heat transfer performances of the direct dry cooling system.Because the flow and heat transfer problems of the air-cooled island spans multiple scales in geometric dimensions,the experimental method is hard to realize while the numerical simulation method is usually used.Therefore,it is necessary to discuss and analyze the accuracy of simplified lumped parameter fan model(i.e.,the simplified model)used in the previous simulation work.[Methods]Based on the numerical simulation method,the real model containing the fan blade fan model(real model)model and the simplified model were both built.Under different weather conditions,the transport properties of the direct dry cooling system were studied.The comparison and analysis of the air-side pressure field and flow field distributions were conducted.Furthermore,the pressure drops and flow rate of the cooling air through the axial flow fan in each air-cooled condenser cell of the direct dry cooling system with different fan models were analyzed and compared.[Results]The difference between the real model and the simplified model is mainly reflected for the axial flow fans with low flow rates,and the difference becomes more obvious with the increase of wind speed.[Conclusions]The results of this paper can provide reference for improving the accuracy of numerical simulation of the direct dry cooling system.