烧结型多孔管的污垢特性

Fouling characteristics of sintered porous surface tubing

在恒热流密度情况下,以CaSO4溶液为介质,研究了烧结型多孔管在池沸腾过程中的污垢特性。结果表明:与光滑管相比,多孔管在不同浓度的CaSO4溶液中都具有阻垢特性,浓度增大污垢热阻的渐近值增大,但当浓度增大到一定程度后,污垢曲线由渐近线型过渡到直线型。通过对两种换热管表面和污垢表面的扫描电镜(SEM)分析,对多孔管的阻垢机理进行了解释。发现多孔表面的CaSO4晶体形状为六棱柱体,晶粒更加细小,约为光滑表面晶粒尺寸的1/2.5,且污垢层更薄。

The experiments on the fouling characteristics of sintered porous surface tubing （SPST） in pool boiling were carried out, with CaSO4 solution as a working fluid, The experimental results showed that SPST possessed better anti-fouling ability compared with smooth surface tube （SST）. The asymptotic fouling thermal resistance increased with increasing concentration of solution. However, transition of fouling curve from asymptotic line to straight line was observed when concentration reached a specific level. An analysis of tubing surface and fouling surface of SPST and SST was made by scanning electronic microscopy （SEM） to interpret the anti-fouling mechanism of SPST. It was observed that the crystal grain of CaSO4on SPST surface was hexaprism-shaped and 1/2.5 size of that from SST surface with a thinner fouling layer.