共查询到20条相似文献,搜索用时 52 毫秒
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控制凝汽器冷却水侧污垢的措施邵社会淮北市纺织印染动力公司汽轮机凝汽器是以循环冷却水介质的换热设备。现在许多地区使用的循环水大部分是地下水及河水。由于地下水的硬度高,河水中夹杂大量排污水,其硬度及泥沙含量较高。因此,在汽轮机凝汽器冷却水侧(以下简称水侧... 相似文献
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管材种类和污垢对凝汽器传热性能的影响 总被引:1,自引:0,他引:1
用凝汽器热力计算中的分布计算公式,对电厂常用的黄铜管HSn70-1、钛管TA2、奥氏体不锈钢管304、317L,铁素体不锈钢管444、SEA-CURE(海优)进行了传热性能的计算,定量分析研究了管材的导热系数和污垢对凝汽器传热性能的影响。结果表明,尽管不同管材的导热系数相差数倍,常用管材凝汽器的总传热系数K差别一般不到6%,有污垢时差别进一步缩小;污垢热阻是控制热阻,0.015mm碳酸钙垢就占总热阻的50%以上,使K降低一半左右;管壁热阻占比最小,清洁时约为3%~11%,0.015mm碳酸钙垢时,约占总热阻的1.5%~6%。 相似文献
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提出了一种基于试验基础上的计算凝汽器传热系数空气侧修正系数的新方法,由这种方法确定的凝汽器传热系数空气侧修正系数是凝汽器内空气含量的单值函数,即cα=f,所以能够准确地反映凝汽器内空气含量对凝汽器传热系数的影响。将此关系应用于凝汽器清洁率的测定计算,实现了凝汽器汽侧空气量对传系数的影响和水侧脏污对传热系数的影响这二者的分离,为凝汽器的合理清扫提供了依据。 相似文献
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分析了别尔曼公式和美国传热学会(HEI)公式进行凝汽器清洁系数的在线计算的可行性,对HEI公式进行数学分析并对各分量求导,可得变工况下凝汽器管束的传热系数与冷却管内水流速度、冷却水进口温度、管径及壁厚、管束的清洁系数之间的定量关系,并由此得出清洁系数,可为凝汽器清洗提供依据. 相似文献
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影响汽轮机凝汽器真空主要因素作用分析 总被引:2,自引:0,他引:2
影响汽轮机凝汽器真空的因素甚多。为使在设计与运行中能更好地理解和掌握调节真空的手段,对主要影响真空因素的机理进行分析,提出真空变化的计算公式,并通过具体机组的数据(引进型300MW机组)说明各主要影响真空因素单独作小量改变时真空的变化程度。 相似文献
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The effect of condenser heat transfer on the energy performance of a plate heat pipe solar collector
For a novel prototype solar collector, using a plate heat pipe, condenser heat transfer was analysed in detail. The condenser has the shape of a rectangular channel. Flow and heat transfer of water in the rectangular channel was modelled and the heat transfer coefficient assessed, using the Fluent code. Under typical operating conditions a mixed convection situation occurs. The channel is inclined and heating is through one wall only (upper channel surface). The range of temperature differences considered was similar to the one verified under real operating conditions, covering a wide range of Grashof numbers. Results showed that the Nusselt number is significantly higher than the one for forced convection in a rectangular channel with fully developed boundary layers. In order to enhance heat transfer, a modification to the rectangular channel was analysed, using baffles to improve flow distribution and increase velocity. The effect of this modification on collector energy performance (efficiency) was assessed. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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多管程平行流微通道冷凝器的管程设计方案对换热器管内热力性能影响较大。但目前一直尚未有对其管内换热系数和压降进行理论预测的较为简单可行方法。本文针对各管程工质流量可变,平均干度可变的多管程平行流冷凝器管内热力参数提出一种分程计算方法:在假设管壁温度不变及同管程内流量均匀分配的前提下,采用了Koyama与Wang冷凝换热模型,以及Zhang和Koyama提出的摩擦压降模型,建立了壁温与热流量之间的关系式,通过迭代求得管内平均换热系数和压降的理论值。以一个商用R134a、流程分配为12-8-8-6微通道冷凝器作为示例,用理论和实验方法分别得到了其管内冷凝平均换热系数和压降。结果表明,二者的偏差均落在30%以内。其中Koyama和Zhang 提出的模型预测偏差较小,分别为-4.96%~11.31%,0.42%~25.14%。 相似文献
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The experimental study was performed on five eccentric radial heat pipes with two outer-tube diameters.The test range can be given as follows,working fluid filling ratio Ω=44%~83%,heat flux q=10000W/m2~32000W/m2,and working temperature tv=50 ℃~120 ℃.The correlations between radial heat pipe heat transfer performance and filling ratio,heat flux,working temperature were studied in the experiment.Based on linear regression of experimental data,the relationship between heat pipe equivalent heat resistance R and working temperature tv,heat flux q and filling ratio Ω was obtained. 相似文献
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曲线拟合法是换热器传热性能实验中经常用到的一种方法,但传统的曲线拟合法存在较多的缺陷。所介绍的曲线拟合法限定条件较少,实用性强。对气体采用温度修正函数时,能够扩大该曲线拟合法适用的温度变化范围。当两侧的流体种类和流体通道相同时,其优点将更加明显。 相似文献
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This paper presents an experimental analysis of a single pass solar air collector with, and without using baffle fin. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. An experimental study has been conducted to investigate the effect of roughness and operating parameters on heat transfer. The investigation has covered the range of Reynolds number Re from 1259 to 2517 depending on types of the configuration of the solar collectors. Based on the experimental data, values of Nusselt number Nu have been determined for different values of configurations and operating parameters. To determine the enhancement in heat transfer and increment in thermal efficiency, the values of Nusselt have been compared with those of smooth duct under similar flow conditions. 相似文献
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阐述了目前建筑外墙围护结构传热系数检测方法存在的一些问题,分析了含湿量对墙体传热系数的影响,针对存在的问题结合夏热冬暖地区气候条件,提出了一种可操作的科学的试验室检测方法,采用调节室调节的方式以快速达到检测的要求,大大方便了节能验收和工程质量控制。 相似文献