内循环流化床内置床换热器传热特性试验研究

发布时间：2018-05-19 06:26

本文选题：流化床 + 内置床换热器　；参考：《中国电机工程学报》2016年08期

【摘要】：在2.5MW(t)内循环流化床锅炉中试装置上,用自制的传热测试管,进行内置床换热器内传热状况的测定与分析。试验测量换热器中埋管管束表面与床层间的换热系数,研究了流化风速、颗粒粒径、床层温度对平均换热系数的影响规律,分析了埋管表面周向局部对流换热系数的分布状况。结果表明:当换热器内流化风速较小时,换热系数随风速的增加而变大,到达最佳流化风速时,换热系数达到最大值,之后随着风速的增加,换热系数稍有降低,然后趋于定值;颗粒粒径越小,对埋管表面的换热效果越好;埋管表面换热系数随床层温度的升高而增大;埋管的背风面换热系数总体大于迎风面,且随着风速的增加,分布趋向于均匀。针对此型内循环流化床内置床换热器中水平埋管,提出了其表面换热系数的试验关联式,较好地将试验值与预测值的偏差控制在25%以内。
[Abstract]:The heat transfer in the inner circulating fluidized bed boiler was measured and analyzed by using the self-made heat transfer test tube in a 2.5 MW / t inner circulating fluidized bed boiler. The heat transfer coefficient between the surface of buried tube bundle and the bed was measured experimentally. The influence of fluidization velocity, particle size and bed temperature on the average heat transfer coefficient was studied. The distribution of local convection heat transfer coefficient around the buried tube surface was analyzed. The results show that the heat transfer coefficient increases with the increase of the wind speed when the fluidization velocity is small in the heat exchanger, and reaches the maximum value at the optimal fluidization wind speed, and then decreases slightly with the increase of the wind speed. The smaller the particle size, the better the heat transfer effect on the surface of buried pipe. The heat transfer coefficient of buried pipe surface increases with the increase of bed temperature, and the heat transfer coefficient of buried tube is generally larger than that of upwind surface, and with the increase of wind velocity, the heat transfer coefficient of buried tube surface is higher than that of upwind surface. The distribution tends to be uniform. Aiming at the horizontal buried tube in this type of inner circulating fluidized bed heat exchanger, the experimental correlation formula of its surface heat transfer coefficient is put forward, and the deviation between the test value and the predicted value is better controlled within 25%.
【作者单位】：能源热转换及其过程测控教育部重点实验室(东南大学);江苏方天电力技术有限公司;
【基金】：“十二五”国家科技支撑计划项目(2012BAA02B01-02)~~
【分类号】：TK229.66

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