风力机与直接空冷系统耦合的数值模拟研究

发布时间：2018-03-30 21:13

本文选题：风力机　切入点：直接空冷系统　出处：《华北电力大学(北京)》2016年硕士论文

【摘要】：在我国北方“富煤缺水多风”地区,风力发电技术与直接空冷系统应用十分广泛。环境风会显著影响空冷凝汽器的换热性能。空气流过风力机流速会降低,通过风力机和空冷岛耦合运行,提高空冷岛性能并减少厂用电率,实现能源的优化利用。本文采用数值模拟的方法,研究了在空冷岛外部布置风力机对空冷凝汽器流动传热性能的影响。首先,根据动量叶素理论建立了三维实体风力机模型,模拟验证了模型的可用性,并得到了风力机在设计风速时尾流流场的变化规律；建立了三维实体风力机与空冷岛耦合模型,在侧面来风、较大风速情况下,选取固定高度4种不同间距的布置方案,对比分析了空冷岛换热量的变化规律,并结合空冷岛周围流线图和温度云图,分析了“热风回流”和“倒灌”现象产生的原因。结果表明较近的布置有利于提高空冷岛的质量流量和换热量,迎风单元的性能有一定改善,但随环境风速增大,改善效果越来越不显著；最后,使用致动盘风力机模型替代三维实体风力机,将风力机简化为一个产生压强差的平面,减小计算量,模拟了在侧面来风和正面来风两种风向、较大风速时,风力机布置2种不同高度布置对空冷岛性能的影响。结果表明,较高的布置方案能降低空冷平台上方环境风速,减弱环境风对空冷岛出口空气的压制作用,削弱了热风回流现象。较低布置对迎风单元换热量提升有帮助,但整体改善效果不如较高布置。2种布置侧面来风比正面来风时空冷岛改善效果好。研究结果为进一步优化空冷岛的换热性能提供参考。
[Abstract]:The technology of wind power generation and direct air cooling system are widely used in the area of "rich coal, short water and more wind" in the north of China.The ambient wind will significantly affect the heat transfer performance of the air-cooled condenser.The velocity of air flowing through the wind turbine will decrease, and the performance of the air-cooled island can be improved by coupling the wind turbine with the air-cooled island, and the utilization of energy can be optimized.In this paper, the effect of wind turbine arrangement on the flow heat transfer performance of air-cooled condenser is studied by numerical simulation.Firstly, the three-dimensional solid wind turbine model is established according to the momentum and leaf element theory. The availability of the model is verified by simulation, and the variation law of the wake flow field of the wind turbine is obtained when the wind speed is designed.The coupling model of three-dimensional solid wind turbine and air-cooled island is established. Under the condition of side wind and large wind speed, four different arrangement schemes with fixed height are selected, and the variation law of heat transfer of air-cooled island is compared and analyzed.The causes of the phenomenon of "hot air return" and "inverted irrigation" are analyzed by combining the streamline diagram and temperature cloud chart around the air-cooled island.The results show that the near arrangement is beneficial to improve the mass flow and heat exchange of the air-cooled island, and the performance of the upwind unit is improved to some extent, but with the increase of the ambient wind speed, the improvement effect is less and less remarkable.Using the model of actuated disk wind turbine instead of three-dimensional solid wind turbine, the wind turbine is simplified as a plane that produces pressure difference, and the calculation is reduced, and the wind direction of side wind and front wind are simulated, and the wind speed is large.The effect of two different height arrangements on the performance of air-cooled islands.The results show that the higher arrangement scheme can reduce the ambient wind speed over the air-cooled platform, weaken the suppression of the ambient wind on the air cooling island outlet air, and weaken the hot air return phenomenon.The lower arrangement is helpful to the heat transfer of upwind units, but the overall improvement effect is not as good as that of the higher arrangement of .2 types of side wind than the positive wind to improve the space-time cold island.The results provide a reference for further optimization of heat transfer performance of air-cooled islands.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM614;TM621

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