600MW直接空冷风机群流体动力学特性研究

发布时间：2018-03-14 00:48

本文选题：直接空冷机组　切入点：风机群　出处：《北京交通大学》2011年硕士论文　论文类型：学位论文

【摘要】：直接空冷风机运行情况对整个凝汽器的换热效果起着决定性作用。本文基于充分利用轴流风机的调频功能,通过数值模拟方法研究风机群并联运行规律,研究结果可以为电厂实现风机单机或局部调控提供一定参考,并为改善直接空冷凝汽器的换热能力和减少风机耗电量提供基础数据。首先分析了在有、无风环境下,空冷风机群并联运行时动力学特性。研究结果表明：无风时中间风机进风量较多,而且各风机的容积效率差距较小,约为0.968～0.98；有风时各风机容积效率差距较大,约为0.55～0.93,有风时风机进风温度比无风时高。在有风群抽规律的基础上,进一步分析环境因素对风机群运行特性的影响。主要研究环境风速、风向和风温等对风机群运行规律的影响。研究结果表明：随着风速提高,各风机容积效率不断降低,靠近来流的风机下降幅度更大,最大可达到风速每增加1m/s,容积效率约下降0.13；随风向角增大,风机总进风量先减小后增多,在45°时最少。分析了加装不同形状挡风墙、导流板和挡板时风机群并联运行特性。研究结果表明：加装曲面挡风墙时,靠近来流的风机容积效率都提高；挡风墙全凹时不仅可以增加风机进风量,而且减小风机进风温度；沿来流方向后排单元间加装挡板,风机总的进风量比未加挡板时多增加11m3/s；加装导流装置后,各风机的容积效率均增大,最多增加7%,随着导流装置与风机平面距离的增加,各风机进风量会增加,但增加幅度越来越小通过正交试验法分析风速、挡风墙形状、导流板和挡板综合作用时,各因素影响的主次关系,得出低风速下,加内凹挡风墙,沿来流方向后排单元间加挡板,在风机平面4m处加导流装置,更有利于风机吸风。本文研究结果对电厂空冷岛设计和风机运行调节具有一定的指导意义。
[Abstract]:The operation of the direct air cooler plays a decisive role in the heat transfer effect of the whole condenser. Based on the full use of the frequency modulation function of the axial fan, the parallel operation law of the fan group is studied by numerical simulation. The results can provide some reference for the realization of single or local control of fan in power plant, and provide basic data for improving the heat transfer capacity of direct air-cooled condenser and reducing fan power consumption. Firstly, the dynamic characteristics of air-cooled air turbine cluster in parallel operation are analyzed in the presence and absence of wind. The results show that the air intake of the intermediate fan is more and the volume efficiency difference of each fan is small when there is no air. The volume efficiency of each fan has a large difference, about 0.55 ~ 0.93, and the inlet air temperature of the fan with wind is higher than that with no wind. On the basis of the extraction law of wind group, the influence of environmental factors on the operating characteristics of fan group is further analyzed. The effects of environmental wind speed, wind direction and wind temperature on the operation law of fan group are studied. The results show that: with the increase of wind speed, The volume efficiency of each fan decreases continuously, and the fan close to the incoming flow decreases by a greater extent, with the maximum wind speed increasing by 1 m / s, the volume efficiency decreases by about 0.13. With the increase of the wind direction angle, the total air intake volume of the fan decreases first and then increases. At the minimum of 45 掳, the parallel operation characteristics of wind turbines with different shapes, baffles and baffles are analyzed. The results show that the volume efficiency of the fan near to the flow is improved when the curved windshield is installed. When the windshield wall is fully concave, it can not only increase the air intake rate of the fan, but also reduce the inlet air temperature of the fan. When the air intake rate of the fan is increased by 11 m3 / s, the total air intake rate of the fan is increased by 11 m3 / s compared with that without the baffle. After the installation of the flow guide device, The volume efficiency of each fan is increased, and the maximum increase is 7. With the increase of the distance between the diversion device and the fan plane, the air volume of each fan will increase, but the increase will be smaller and smaller. Through the orthogonal test method, the main and secondary relationships of the factors affecting the wind speed, the shape of the windshield wall, the guide plate and the baffle are analyzed, and the conclusion is drawn that under the low wind speed, the inner concave windshield wall is added, and the baffle is added to the back row units along the direction of the incoming flow. It is more advantageous for the fan to absorb air by adding the diversion device at the plane of 4 m. The results of this paper have certain guiding significance for the design of air cooling island and the regulation of fan operation in power plant.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH432.1

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