W火焰锅炉结渣特性数值模拟

采用结渣模型耦合气固两相流动燃烧模型，对一台DG1025/18.2-II14型W火焰锅炉结渣特性进行了数值模拟，结合现场运行状况，对结渣位置、程度及原因进行了分析。结果表明，该锅炉的结渣位置主要是下炉膛侧墙、拱部燃烧器区域和前后墙局部区域。炉膛中心区域温度比两侧高，气流膨胀更迅速，压力更高，挤压两侧气流沿炉膛宽度方向向侧墙运动，产生偏斜，火焰冲刷侧墙，是导致W火焰锅炉侧墙结渣的根本原因。锅炉变工况运行时，切停或切换部分燃烧器，使炉内局部空气动力场偏斜，冲刷已关闭了燃烧器的拱部和前后墙区域，则是导致拱部燃烧器区域和前后墙局部区域结渣的主要原因。

Numerical Simulation of the Ash Deposition Characteristics in a W-flame Boiler Furnace

The numerical simulation of the ash deposition characteristics in the furnace of a DG1025/18.2-Ⅱ14-type W-flame boiler was carried out by using the slagging models coupled with the gas-solid two phase flows combustion models. Combined with the operational status, some detailed analysis on the ash deposition position, extent and reason was represented. The results show that the ash deposit is mainly on the side, front and rear walls of the lower furnace and the burner regions of the furnace arches. The flue gas pressure in the central region of the furnace is higher than that on the both sides because of the more rapid expansion of the flue gas under the higher temperature. Therefor, the flue gas in the furnace center makes the flue gas on the both sides deflective and move to the side walls, and the pulverized-coal flame scours the side walls. It results in the ash deposition on the side walls. In off-design operational conditions, such as stopping some burners, the local flow field is asymmetric and scours the local arch burner, front and rear wall regions where the stopped burners locates. It is the main cause for the ash deposition on the arch burner regions and the front and rear wall regions.