An ash deposition suppression technique in flue gas heat exchanger was proposed,and the numerical study on the heat transfer performance and ash deposition behavior of a flue gas heat exchanger with a 6-row tube arrangement was conducted.Then,the orthogonal tests were adopted to analyze the influence of the geometric parameters on the heat exchanger performance.The primary and secondary influencing sequences of the three factors were obtained,and then the optimal combination of the geometric parameters was determined for the suppression of ash deposition.The results showed that the factors influencing the ash deposition rate are arranged in a descending order as follows:the diameter of the added cylinders,the spacing between added cylinder and heat exchange tube,and the setting angle of added cylinder.However,the setting angle is the most significant factor for heat transfer performance.Considering the ash deposition rate and heat transfer performance,the optimal combination was determined as the diameter of 6 mm,spacing of 4 mm and setting angle of 40°.Taking the ash deposition rate as the optimization objective under optimal conditions,the ash deposition rate was decreased by 55.1％ compared with the heat exchanger without added cylinders,which can realize efficient recovery and utilization of waste heat from industrial flue gas.%为了探讨能够减轻积灰的烟气余热回收换热器结构布置,提出了在换热管后加附属圆柱的方式,对6排管顺排布置换热器的流动传热及积灰特性进行了数值研究;其次,采用正交试验法分析了附属圆柱的各因素组合方式对换热器积灰及流动换热性能的影响,获得了影响积灰及换热性能的主次要因素;最终得出能够有效降低颗粒沉积率的较优组合结构参数.结果表明:对于沉积率指标,附属圆柱直径是最敏感的因素,附属圆柱与换热管间距次之,附属圆柱安装角影响最小,而影响换热性能的最敏感因素为附属圆柱安装角;综合考虑颗粒沉积率与换热性能,选择的最优方案是附属圆柱直径为6 mm、圆柱与换热管间距为4 mm、附属圆柱安装角为40°;将颗粒沉积率作为优化目标,按照正交设计的最优组合管束与光管管束相比,其颗粒沉积率降低约55.1％,能够实现工业烟气余热的高效回收利用.
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