共查询到19条相似文献,搜索用时 76 毫秒
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以某台1 000MW超超临界塔式锅炉作为研究对象,采用区域法建立了二维小区换热模型,简化了炉内辐射换热与对流换热,对不同锅炉负荷下对流换热量占炉膛高度方向各分区换热量、炉膛总换热量的比例以及沿炉膛宽度方向水冷壁壁温的分布进行了研究,并与实测数据进行了比较.结果表明:水冷壁壁温计算值与试验值的最大偏差率为5.26%,均呈现中间高、两端低的分布趋势;对流换热量最多可使壁温计算值提高16.7K,计算精度提高3.30%;计算所得的水冷壁壁温最高值为523.5℃,未超出材料的允许温度,且有4.8%的安全裕度. 相似文献
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为研究超临界循环流化床锅炉水冷壁的变形问题,在实炉测量某600 MW超临界循环流化床锅炉炉膛水冷壁壁温分布的基础上,采用数值模拟方法对距离布风板30m高度处4.6m×2m区域的水冷壁管进行了热应力分析。结果表明:80%负荷工况下,距离布风板30m高度处区域的水冷壁管沿炉膛高度方向的温度变化率较大,热应力分布极不均匀;计算区域的水冷壁管整体向下膨胀,由于存在膨胀偏差,水冷壁向火侧向炉内凸起变形,最大变形量约1.14mm;对于整个水冷壁管屏而言,存在的变形量叠加会加剧水冷壁磨损,甚至造成爆管事故。 相似文献
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1000MW超超临界锅炉水冷壁壁温计算 总被引:1,自引:0,他引:1
采用分区计算简化大容量高参数超超临界锅炉炉内辐射、对流传热模型,研究炉膛水冷壁热负荷及壁温的空间分布情况,并与试验数据进行了对比,计算结果与试验值之间的偏差较小,最大为5.72%.该模型与算法可给出不同锅炉负荷条件下,水冷壁壁面热负荷与壁温沿炉膛宽度方向的分布规律.结果表明,水冷壁热负荷与壁温均呈现出中间高两端低的弧形分布.四角切圆燃烧锅炉火焰位置对炉内传热有很大影响.模拟计算可为超超临界锅炉的运行提供参考,预测了在材料允许温度范围内,火焰中心偏斜最大不超过2 m. 相似文献
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以上海石洞口第二发电厂引进的由瑞士SULZER和美国CE公司联合设计的600MW超临界变压运行直流锅炉为研究对象,消化吸收引进技术,确定了600MW超临界压力锅炉水冷壁温度场计算中的外边界条件,并与内边界条件研究(倾斜管及垂直管管内传热特性研究)相结合,找到了进行600MW超临界压力锅炉水冷壁温度场计算的新方法。 相似文献
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针对某电厂1 000 MW超超临界塔式锅炉结构特点,采用流动网络系统,根据质量、动量、能量守恒方程,建立了适用于超超临界塔式锅炉水冷壁水动力计算的模型。水动力计算结果得到:某电厂1 000 MW超超临界塔式锅炉在1 000 MW负荷、750 MW负荷和400 MW负荷下,压降计算结果与实炉数据吻合,并且,程序计算得到的上下炉膛出口汽温与某电厂实际运行数据整体上也比较符合。计算结果表明:下炉膛和上炉膛的水冷壁内壁温度、外壁温度、中间点壁温与鳍片温度均处于材料许用范围之内,水冷壁运行是安全可靠的。并对锅炉在400 MW低负荷运行时的流动稳定特性进行了计算校核,校核计算表明:在400 MW负荷下,流动处于稳定区,水冷壁不会发生流动不稳定性。 相似文献
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以上海石洞口第二发电厂引进的由瑞士SULZER和美国CE公司联合设计的600MW超临界变压运行直流锅炉为研究对象,消化吸收引进技术,确定了600MW超临界压力锅炉水冷壁温度场计算中的外边界条件,并与内边界条件研究(倾斜管及垂直管管内传热特性研究)相结合,找到了进行600MW超临界压力锅炉水冷壁温度场计算的新方法. 相似文献
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Junfu Lu Long Yu Guangxi Yue Hairui Yang Jiansheng Zhang Man Zhang Zhongming Yang 《Frontiers of Energy and Power Engineering in China》2008,2(2):134-139
The future of circulating fluidized bed (CFB) combustion technology is in raising the steam parameters to supercritical levels.
Understanding the heat flux distribution on the water wall is one of the most important issues in the design and operation
of supercritical pressure CFB boilers. In the present paper, the finite element analysis (FEA) method is adopted to predict
the heat transfer coefficient as well as the heat flux of the membrane wall and the results are validated by direct measurement
of the temperature around the tube. Studies on the horizontal heat flux distribution were conducted in three CFB boilers with
different furnace size, tube dimension and water temperature. The results are useful in supercritical pressure CFB boiler
design.
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Translated from Journal of Power Engineering, 2007, 27(3): 336–340 [译自: 动力工程] 相似文献
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本文应用有限差分法离散一维变物性非稳态导热方程进行编程,对墙体在不同辐射条件,湿度为30%和70%两种情况下,以及外壁风速在1m/s和3m/s情况下的非稳态导热过程进行计算,得出墙体在不同情况下的温度分布。通过对温度分布和不同截面位置温度达到一天内的峰值时间相对外壁面温度达到一天内的峰值响应时间加以分析,得出了迟滞时间与所在位置的函数关系式。同时对空气湿度变化和外壁面风速改变对墙体导热过程带来的影响进行了分析。 相似文献
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燃煤锅炉水冷壁爆管严重影响锅炉的运行,严重的爆管直接导致锅炉灭火.本文通过对某锅炉的运行分析,了解了水冷壁爆管的主要和次要因素,并提出一些可以解决的办法. 相似文献
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通过实践经验总结、分析了锅炉汽包壁温差产生的原因,指出了汽包壁温差大的危害,提出了电站锅炉汽包壁温差在运行中的控制及预防措施。 相似文献
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In order to expand the study on flow instability of supercritical circulating fluidized bed (CFB) boiler, a new numerical computational model considering the heat storage of the tube wall metal was presented in this paper. The lumped parameter method was proposed for wall temperature calculation and the single channel model was adopted for the analysis of flow instability. Based on the time-domain method, a new numerical computational program suitable for the analysis of flow instability in the water wall of supercritical CFB boiler with annular furnace was established. To verify the code, calculation results were respectively compared with data of commercial software. According to the comparisons, the new code was proved to be reasonable and accurate for practical engineering application in analysis of flow instability. Based on the new program, the flow instability of supercritical CFB boiler with annular furnace was simulated by time-domain method. When 1.2 times heat load disturbance was applied on the loop, results showed that the inlet flow rate, outlet flow rate and wall temperature fluctuated with time eventually remained at constant values, suggesting that the hydrodynamic flow was stable. The results also showed that in the case of considering the heat storage, the flow in the water wall is easier to return to stable state than without considering heat storage. 相似文献
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The exergy transfer characteristics of fluid flow and heat transfer inside a circular duct under fully developed laminar and turbulent forced convection are presented. Temperature is kept constant at the duct wall. The exergy transfer Nusselt number is put forward and the analytical expressions for exergy transfer Nusselt number are obtained as functions of heat transfer Nusselt number, Reynolds number, Prandtl number, etc. The variations of the local and mean convective exergy transfer coefficient, non-dimensional exergy flux, exergy transfer rate, etc. with operating parameters are presented graphically. By reference to a smooth duct and taking air as working fluid, a numerical analysis of the influence of the Reynolds number and non-dimensional cross-sectional position on exergy transfer characteristics has been conducted. The results show that the process parameters and configuration in the fluid flow and heat transfer inside a duct should be properly selected so that the forced convection process could have the best exergy utilization. In addition, the results corresponding to the exergy transfer and energy transfer are compared. 相似文献
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An empirical approach is proposed to estimate the bulk temperature in practical laminar tube flow. To examine the correlation, heat transfer in different types of tubes with wall conduction and uniform constant heat flux at tube outer wall surface is numerically investigated. The predictions from the proposed correlation match well with the numerical results in all the cases studied for air flow in the Pe range from 105 to 1032 and for water flow in the Pe range from 70 to 700. The method is further testified via comparison with experimental data and numerical results of mini (micro)-channel water flow available in literature. 相似文献
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Seyed Abdolmehdi Hashemi Zaher Mohammed Abed Alsulaiei Mahdi Mollamahdi 《亚洲传热研究》2020,49(4):2282-2296
In the present analysis, the flame stabilization and temperature distribution within a premixed burner contain porous wall are studied experimentally. The effects of inner diameter, length, and pore density of the porous wall, thermal load, equivalence ratio, and the inlet velocity of the fuel‐air mixture on these are studied. The fuel used in this study is natural gas and the porous wall is SiC (silicon carbide) ceramic foam. The experimental results clearly indicate that the axial temperature along the porous wall increases when the inner diameter of the porous wall decreases and its length increases. The porous wall temperature with an inner diameter of 40 mm, length of 66 mm, and pore density of 30 PPI (pores per inch) has the highest temperature among the examined states. The results of studying the effect of the porous wall on flame stability show that the flame stability limit has a direct relationship with the length and pore density of porous wall and an inverse relationship with the inner diameter of the porous wall. Also, it is found that the porous wall has the highest temperature causes the maximum flame stability limit. 相似文献