灰尘堆积对螺旋翅片管式换热器换热性能的影响

Influence of Dust Deposition on the Heat Transfer Performance of Spiral Finned Tube Heat Exchanger

摘要: 针对翅片管式换热器表面积灰现象，采用CFD-DEM耦合方法研究了表面积灰的过程及两种典型积灰形式对换热性能的影响。根据灰尘颗粒的运移特征，将整个积灰过程归纳为三个阶段，依次对应未形成污垢层、形成较薄的污垢层和污垢层加厚。表面的灰尘堆积会增加翅片的有效厚度，且由于灰尘的导热系数远低于翅片金属材料，会额外产生热阻，进而直接降低冷空气与翅片间的热交换效率。当夹缝间发生灰尘堵塞时，更多的冷空气将被迫从侧边流入，导致侧边冷空气流量显著增加。该情况虽会对局部区域的温度分布造成一定扰动，但对换热器整体温度的影响相对有限。

Abstract: To address the surface dust deposition issue of finned tube heat exchangers, this study employed the CFD-DEM coupling method to systematically investigate the surface dust deposition process and the effects of two typical dust deposition patterns on heat transfer performance. Based on the migration characteristics of dust particles, the entire dust deposition process was categorized into three stages, which correspond sequentially to the states of no fouling layer, formation of a thin fouling layer, and thickening of the fouling layer. Dust deposition on the fin surface increases the effective thickness of the fins; moreover, as the thermal conductivity of dust is far lower than that of the fin metal material, additional thermal resistance is generated, which directly reduces the heat exchange efficiency between the cold air and the fins. When dust clogging occurs in the fin gaps, more cold air is forced to flow in from the side edges, resulting in a significant increase in cold air flow rate at the sides. Although this phenomenon causes a certain disturbance to the temperature distribution in local regions, its impact on the overall temperature of the heat exchanger is relatively limited.