大型间接空冷机组变工况特性研究

发布时间：2018-07-28 13:49

【摘要】：随着空冷技术的不断发展,超临界间接空冷机组在富煤缺水地区将得到广泛应用。针对间接空冷散热器不同的翅片管束结构型式,选取对应的翅片管束流动和传热关联式,并考虑空冷塔各个环节的流动阻力以及对应不同散热器壁温的抽吸力计算公式,建立了能够体现空冷塔流动和传热性能的物理数学模型。针对给定塔形进行了如下分析,在不同环境风速下,由于空气绕流空冷塔引起散热器单元进口空气压力分布变化,导致空冷塔散热能力的改变,进而对凝汽器背压造成的影响。在环境气温变化时,散热器单元进口空气温度发生变化,致使空冷塔散热能力发生变化,对凝汽器背压造成的影响。在机组负荷发生变化时,由于冷却水流量与温度发生变化,使得空冷塔散热能力发生变化,对凝汽器背压造成的影响。建立了电站间接空冷系统变工况特性数学模型,并给出计算的流程图,应用Matlab软件编制了计算程序,为间接空冷机组变工况特性的分析奠定了理论基础。以典型2×660MW间接空冷机组为例,分析了间接空冷机组背压随环境风速、环境温度、排气流量、循环水流量的变化规律。为指导电站空冷系统运行和设计提供了参考。
[Abstract]:With the continuous development of air cooling technology, supercritical indirect air cooling units will be widely used in areas rich in coal and water shortage. In view of the different finned tube bundle structure types of indirect air cooling radiator, the corresponding flow and heat transfer correlations of the fin tube bundle are selected, and the flow resistance of each link of the air cooling tower and the calculation formula of suction force corresponding to different radiator wall temperature are taken into account. A mathematical model of air cooling tower flow and heat transfer is established. The following analysis is made for the given tower shape. Under different ambient wind speeds, the air pressure distribution at the inlet of the radiator unit changes due to the air flow around the air cooling tower, which leads to the change of the cooling capacity of the air cooling tower and the effect on the back pressure of the condenser. When the ambient temperature changes, the inlet air temperature of the radiator unit changes, which results in the change of the cooling tower heat dissipation capacity and the influence on the back pressure of the condenser. When the unit load changes, the cooling water flow and temperature change, which results in the change of cooling tower heat dissipation capacity and the influence on the back pressure of condenser. The mathematical model of variable working condition characteristic of indirect air cooling system of power station is established, and the flow chart of calculation is given. The calculation program is compiled by using Matlab software, which lays a theoretical foundation for the analysis of variable working condition characteristic of indirect air cooling unit. Taking a typical 2 脳 660MW indirect air-cooled unit as an example, the variation of backpressure of indirect air-cooled unit with ambient wind speed, ambient temperature, exhaust flow rate and circulating water flow rate is analyzed. It provides a reference for the operation and design of air cooling system in power station.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM621

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