共查询到18条相似文献,搜索用时 109 毫秒
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空冷岛运行优化中,需要将汽轮机、空冷凝汽器及空冷岛风机的特性综合起来进行分析。在综合直接空冷机组冷端各个组成部分,包括空冷凝汽器、低压缸至空冷凝汽器之间排汽管道及空冷岛风机特性的基础上,建立汽轮机排汽背压与空冷岛风机转速的特性关系,为空冷岛运行优化计算创造了条件。 相似文献
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从六个层面介绍了山西漳山发电有限责任公司1号300MW机组所配三排管直接空冷凝汽器管束冻结的原因,并提及三排管直接空冷凝汽器所存在某些不足及其改进建议,供已投运的三排管直接空冷凝汽器的改造和将来建设三排管直接空冷凝汽器机组的设计参考。 相似文献
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直接空冷凝汽器加装防风网的数值模拟 总被引:2,自引:0,他引:2
利用Fluent软件,以国内某600 MW直接空冷机组为例,对迎风侧2个相邻空冷凝汽器进行了数值模拟,得到了不同环境横向风速下空冷凝汽器的传热效率随着风速的增大而降低,而且被环境风冲刷越严重的凝汽器受影响程度越大的结论.针对横向风对空冷凝汽器传热效率的影响,在凝汽器挡风墙下延方向加装了防风网.对加装防风网后的空冷凝汽器进行了数值模拟,分析了防风网的不同结构参数(开孔率、高度)对空冷凝汽器传热效率的影响,结果表明:在加装防风网后凝汽器传热效率显著提高,防风网的结构参数对其防风效果有明显影响,为直接空冷机组的防风网改造提供了理论依据. 相似文献
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自然通风直接空冷系统凝汽器单元"Λ"型布局和传统翅片结构使得冷却空气流过翅片管束时发生严重转向,从而显著影响空冷凝汽器的流动传热性能。提出了一种新型翅片管束,其翅片通道与基管椭圆长轴方向呈一定夹角,使翅片通道方向与塔浮升力方向平行。通过CFD数值模拟和实验验证,获得了采用新型倾斜翅片管束的自然通风空冷凝汽器的空气流场和温度场,计算得到了不同环境风速下空冷凝汽器总换热量的变化规律,并与现有翅片管束的空冷凝汽器性能进行了对比。研究结果表明,采用倾斜翅片空冷凝汽器可以显著改善自然通风直接空冷系统热力性能,降低机组背压,提高空冷机组运行的经济性。 相似文献
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《太阳能》2020,(9)
研究人员对用于火电机组的空冷凝汽器的特性已经开展过广泛的研究,结合太阳能热发电站的选址及其发电过程的特殊性可以看出,应用于太阳能热发电站的空冷凝汽器与应用于火电机组的空冷凝汽器有所区别。以某50 MW塔式太阳能热发电站中空冷凝汽器为研究对象,通过对相关影响因素进行分析并对典型天发电过程进行模拟,得到以下结论:太阳辐照度会对空冷凝汽器产生附加热负荷,影响的大小主要与太阳法向直射辐照度(DNI)、太阳散射辐照度(DHI)和太阳位置有关;在轴流风机出力达到最大之前,轴流风机耗功会随环境温度上升呈指数增长,之后,空冷凝汽器的压力会随着环境温度直线上升;对于需要每天启动的热发电机组来说,太阳辐照度较高的日落时刻的太阳辐照附加热负荷可能会在短时间内急剧增加,从而引起轴流风机耗功大幅度增加;环境温度较高时可能会引起空冷凝汽器压力的急剧升高,这在运行中需要给予特别关注。 相似文献
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《Energy》2005,30(7):968-981
The effects of condensers installed in the stacked air-conditioning plant rooms of a high-rise apartment building were studied numerically. The performance of the condensers was evaluated using the coefficient of performance (COP) and condenser group performance indicator (CGPI) parameters. The effects of wind direction, wind velocity, and the arrangement and location of the condensers were investigated. The performance of condensers above the 30th floor was seriously degraded due to the stacking effects. The heat dissipation performance of the condensers in the higher floors dropped significantly when the frontal wind was greater than 4 m/s and the side wind was greater than 8 m/s. The condenser should be arranged in such a manner that the fan of the condenser faces the outside of the building to exhaust the hot air directly to the outside. To prevent the hot air from reentering the air-conditioning plant room and to allow fresh air to enter instead, the condenser considered in this study must be located at the lower left corner of the air-conditioning plant room. 相似文献
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针对微通道换热器用作汽车空调冷凝器的特点,研制了一套冷凝器单体性能测试试验台,即主机及风洞试验台.该试验台主测风洞系统的换热量采用空气焓差法测试,辅测主机系统的换热量采用制冷剂流量计法测试,并选取两款微通道冷凝器对其进行冷凝换热试验,以验证该试验台的稳定性和准确性.结果表明,该试验台空气侧和制冷剂侧所测得的换热量偏差均在5%以内,满足冷凝器测控要求.根据实验数据得到了冷凝器迎面风速对换热量、空气压降和制冷剂压降的影响规律,为微通道换热器的优化设计及企业的相关研究提供参考. 相似文献
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《Applied Thermal Engineering》2007,27(11-12):1937-1943
Reduction of energy consumption is a major concern in the vapor compression refrigeration cycle especially in the area with very hot weather conditions (about 50 °C), where window-air-conditioners are usually used to cool homes. In this weather condition performance of air condenser window-air-conditioners decrease sharply and electrical power consumption increase considerably. These problems have activated the research programs in order to improve the performance of window-air-conditioners by enhancing heat transfer rate in the condenser. In this article, a new design with high commercialization potential for incorporating of evaporative cooling in the condenser of window-air-conditioner is introduced and experimentally investigated. A real air conditioner is used to test the innovation by putting two cooling pads in both sides of the air conditioner and injecting water on them in order to cool down the air before it passing over the condenser. The experimental results show that thermodynamic characteristics of new system are considerably improved and power consumption decreases by about 16% and the coefficient of performance increases by about 55%. 相似文献
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In terms of reducing the environmental pollution caused by effluent water from typical condensers and the water dependency of small modular reactors, indirect dry air‐cooled condensers (IDACs) are being considered an ultimate heat sink. While the performance of air‐cooled heat exchangers has been investigated thoroughly for decades, evaluations of the condenser performance rely primarily on empirical data. Thus, a method for precisely determining the performance of the IDAC under various environmental and thermal‐hydraulic conditions has not yet been understood. The objective of this study is to experimentally investigate the critical parameter that initiates the deterioration of the condenser performance by varying the cooling duty and water velocity. The investigation is also extended to a parametric study of the air‐cooling conditions using a best‐estimate thermal hydraulic analysis code called multi‐dimensional analysis of reactor safety (MARS‐KS) to suggest a method for designing an IDAC system. Results showed that, for a given cooling duty and water velocity, the condenser exhibited an insufficient performance above a certain cooling water temperature. The temperature was defined as the pressure transition temperature (PTT) that initiates the increase in pressure inside the condenser. The calculation results of MARS‐KS were analysed based on the PTT and was used to suggest methods for designing an appropriate IDAC for the cooling duty and environmental conditions of given target site. 相似文献
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火电站直接空冷凝汽器积灰是影响传热性能的重要因素,研究直接空冷凝汽器积灰对传热性能的影响规律并提出监测措施具有重要意义。通过分析汽轮机背压与汽轮机排汽量、冷却空气流量、凝汽器传热系数、凝汽器总传热面积以及环境温度之间的关系,得到了空冷凝汽器在维持汽轮机排汽量和冷却空气量不变时,汽轮机背压和传热系数之间的关系以及凝汽器积灰对汽轮机背压的影响。研究表明:凝汽器积灰会导致凝汽器传热系数降低,汽轮机背压升高,机组运行经济性下降。设计工况下,当蛇形翅片扁平管结构凝汽器积灰厚度达到1.2 mm时,汽轮机背压将增加50%左右。通过监测空冷机组运行过程中汽轮机背压的变化,可预报积灰的程度,为直接空冷凝汽器清洗提供一定的理论依据。 相似文献