【作者】 张华磊；

【导师】 刘宗德；

【作者基本信息】 华北电力大学（北京） ， 动力机械及工程， 2011， 硕士

【摘要】 循环流化床锅炉水冷壁管磨损是目前阻碍循环流化床锅炉发展的主要瓶颈,研究其磨损机理和采取有效的防磨措施是现在的研究热点。本文首先分析了循环流化床锅炉的磨损机理,以白马电厂锅炉实际数据为基础模拟其内部流场,得出内部流场流动特性,为进一步分析磨损机理提供了依据。通过分析,得到煤粉浓度沿炉膛轴向方向呈上稀下浓及煤粉颗粒沿径向方向呈环-核流动分布。颗粒速度在中心区域较高且方向向上,边壁区速度方向向下这就形成了炉膛物料的内循环流动。计算结果与文献相符。还可以看出在炉膛四角和底部密相区煤粉颗粒速度和浓度都较大,这也是这些部位容易受磨损的主要原因。通过氩弧熔覆的方法,制备出了高性能的Fe-Cr-B系耐磨熔覆层。对在不同电流熔覆下制备的熔覆层的硬度和热影响深度做了分析。分析表明：熔覆层表面硬度高达1200HV,组织均匀,与基体之间冶金结合。对熔覆层做了高温冲蚀实验,结果表明熔覆层的耐磨性能是20G钢的6倍,在高温环境下具有极高的耐磨性能。更多还原

【Abstract】 At present, the wear of water wall tube is the major bottleneck which restrict the development of CFB boilers. It has become the focus of CFB research to study the wear mechanism and look for effective anti-wear measures. In order to analyze the wear mechanism of CFB boiler tube, this paper first simulate the internal flow field of the furnace on the basis of actual data of Baima Power Plant. Simulation results revealed a typical core-annulus flow pattern along the radical direction. The particles flow upward with high velocity at the central region and downward with low velocity near the wall, forming the inner circulation of gas-solid flow. The axial distribution profile of particle concentration show high value at the bottom of the furnace while low in the upper zone. In addition, much higher particle concentration and velocity were observed at the corner of the funace and the bottom part. That is why the tubes in such areas are subject to wear. The computational results agreed with the experimental data reported in the literature. In this study, the anti-abrasive coatings were prepared by using a self-made TIG cladding system. Rapid water cooling condition was applied in order to decrease the deformation during welding process, thus enhanced the performance of the coatings. The micro-hardness and heat affected depth of the coatings were compared under different operation current with the aim of obtaining optimal operation parameters. Further analysis showed that the microstrutures of the coatings are uniform. Metallurgical bonding was formed between the coating and the substrate. Moreover, the micro-hardness of the coating is up to 1200HV, which is six times higher than that of 20G. Therefore, the coating has perfect wear resistance under the environment of high temperature.更多还原