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叙述了变压运行超超临界锅炉水冷壁的运行特点,传热恶化、温度偏差与水动力稳定性的国内外研究结果,提出了对垂直内螺纹管水冷壁质量流速的选取和水动力不稳定性校核的看法. 相似文献
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以东方锅炉(集团)股份有限公司自主开发的600MW超临界“w”火焰锅炉拟采用的031.8x6mm多头优化内螺纹管为研究对象,在多相流试验台上进行了锅炉水冷壁在低负荷条件下的水动力不稳定性试验研究,并对试验结果进行了初步分析,得出了水冷壁发生水动力不稳定的条件。试验表明:东方锅炉自主设计的600MW超临界“w”火焰锅炉水冷壁拟采用的多头内螺纹管在当压力〉6MPa时,试验就不再有密度波型脉动发生,当压力〉9MPa时,就不再有压力降型脉动发生。因此,根据东方锅炉超临界“w”火焰锅炉的设计特点及设计运行参数范围,锅炉运行不会出现水动力不稳定现象,水冷壁水动力是安全的、可靠的。 相似文献
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叙述了超超临界锅炉垂直水冷壁的结构特点和水动力特性,并介绍了内螺纹管垂直管圈水冷壁主要设计参数的选取原则和水动力稳定性的判别方法。 相似文献
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针对1 000 MW超超临界机组锅炉内螺纹管垂直管屏水冷壁变压运行特性进行了理论分析.重点分析了低质量流速下的水冷壁热偏差对流量偏差的影响关系和内螺纹管传热特性以及直流锅炉水冷壁强制流动特性被自然循环特性部分低偿的流动特性. 相似文献
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本文介绍国产30万千瓦UP型直流锅炉水冷壁水动力特性的计算方法及其主要结果,对其流动特性进行了分析并校验了传热恶化,最后提出改进结构的设想。 相似文献
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为解决660 MW超超临界锅炉垂直管圈水冷壁汽温存在偏差、温度波动大和水冷壁出现横向裂纹等问题,进行了试验研究和水动力计算。根据锅炉设计方案,建立了某电厂锅炉流动网络系统的水动力计算数学模型,并在锅炉水冷壁上铺排工质温度测点;根据实炉测量数据,对1号机组270 MW负荷时炉内热负荷和热偏差的分布进行了计算分析;然后调整了节流圈的布置方案,计算调整后的水动力和流动不稳定性。结果表明:调整后出口汽温更加均匀,调整后的方案能更好地防止汽温波动,且不会发生脉动;节流圈调整后中高负荷下的垂直管圈水冷壁汽温分布更均匀,汽温偏差问题明显改善。 相似文献
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通过对角管式蒸汽锅炉侧墙水冷壁的循环原理进行分析,找到了影响再循环管水动力特性的主要因素,并建立了水动力特性实验台,对热负荷和预分离集箱影响再循环管作用的规律了实验研究。 相似文献
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Jie Pan Dong Yang Hui Yu Qin-cheng Bi Hong-yuan Hua Feng Gao Zhong-ming Yang 《Applied Thermal Engineering》2009,29(11-12):2500-2507
Water wall design is a key issue for an ultra supercritical boiler. In order to increase the steam–water mixture turbulization and to prevent the burnout of tubes walls, vertical rifled tubes are applied in Yuhuan power plant boiler which is the first 1000 MW ultra supercritical boiler in China and began to operate in December 2006. Mathematical modeling and thermal-hydraulic analysis are key factors for the successful design and operation of water walls. The water wall system is treated in this paper as a network consisting of circuits, pressure grids and connecting tubes. The mathematical model for predicting the mass flux distribution and metal temperature in water wall is based on the mass, momentum and energy conservation equations. An experiment on the heat transfer characteristics of vertical rifled tube was conducted with the aim to obtain the heat transfer performance and corresponding empirical correlations. The fitting computational formulas are applied in the mathematical model. The presented modeling method is more accurate than the conventional graphic method and can be applied to complex circuit structures. The mass flux distribution and the metal temperature in the water wall are calculated at 35%, 50% and 100% of the boiler maximum continuous rating (BMCR). The results show a good agreement with the plant data. The maximum relative difference between the calculated mass flux and the plant data is 9.7% at 50% BMCR load. The metal temperature difference in the tip of fins in lower circuit 8 is about 3–7 °C at 35% BMCR load. The results show that the vertical water wall in the ultra supercritical boiler of Yuhuan power plant can operate safely. 相似文献
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结合某公司300 MW燃煤UP型直流锅炉低NOx燃烧改造实例,进行了水动力原始偏差测定。同时以70%BMCR作为基准负荷,控制包覆出口压力12 MPa,进水量632 t/h,以50%负荷与30%负荷作为校核试验,并对整个热态启动过程炉内温度状况和水动力情况进行了评述。试验结果表明,低NOx燃烧改造的燃烧系统设计可有效地保护水冷壁,并配合精细的水动力特性调整,使得UP型锅炉的水冷壁安全性大为提高。 相似文献
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电厂中由于锅炉的壁温及使用寿命监测手段比较落后,锅炉四管爆裂问题经常发生,尤其是锅炉过热器和再热器,而过热器和再热器超温爆管直接影响到机组的安全运行和经济性,因此电厂中对锅炉过热器再热器壁温和寿命损耗率的计算显得很重要。对苏制TII-82型锅炉过热器再热器的寿命损耗率的计算进行了研究,根据文中提出的锅炉过热器再热器寿命损耗率计算的模型,以某电厂的1号炉为例,最后计算出寿命损耗率=0.22141,为以后能够开发一套能准确计算锅炉过热器再热器壁温及寿命预测的在线监测与故障诊断系统提供了基础。 相似文献
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The heat-transfer characteristics of two-phase film boiling of nitrogen in tubes with tape-generated swirl flow are described. The swirl flow substantially augments the heat transfer and minimizes the thermal non-equilibrium, which is responsible for the relatively poor performance of boilers without twisted-tape inserts. Assuming thermal equilibrium, it is possible to formulate a relatively simple superposition correlation for both evaporation and superheat regions of the once-through boiler. The correlation gives good prediction of wall temperatures along the tube for the entire range of test conditions. 相似文献
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《Applied Thermal Engineering》2002,22(7):803-814
An experimental study has been undertaken into the enhancement obtained in the heat-transfer coefficients when HIGHFLUX tubes are used in preference to plain tubes while boiling pentane. The study involved two experimental facilities, a single-tube pool boiler and a 241 tube, 17 row by 17 column, thin slice kettle reboiler. The pool boiling results show that the HIGHFLUX tubes produce heat-transfer coefficients that are up to five times larger than their plain tube counterparts. In flow boiling the enhancement is 3–6 times. In both cases, HIGHFLUX tube performance is shown to deteriorate when small degrees of subcooling are present in the liquid. The deterioration still leaves the HIGHFLUX tubes with a significantly higher heat-transfer coefficient than the plain tubes. Existing flow boiling design methodologies are shown to produce performance characteristics that HIGHFLUX tubes do not follow. 相似文献
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燃煤锅炉水冷壁结焦是国内外火力发电厂常见的问题,本文通过对某410 t/h锅炉制粉、着火、燃烬等方面研究分析了解了水冷壁结焦特性,得出了锅炉水冷壁结焦的主要因素,并提出了相应解决办法. 相似文献