关键词: 表面, 结垢, 分形, 界面, 黏附

Abstract: Surface property of material has a great impact on the interfacial adhesion of particle and surface.Rough surfaces were used for studying scale feature of above two indicators.It could conclude from the above study of scale feature of fractal indicators that there existed two regions when fractal indicators change with scale, which were named unstable fractal region and stable region.In the process of analysing the two-dimensional surface contour, we transfered the finding of critical point into solving the quantitative relationship of sampling length and angle α.By the quantitative relationship, angle α could be made 0 to obtain the critical sampling length.As long as the sample length is greater than the critical length, stable fractal region could be obtained, and then the stable fractal dimension could be calculated, which would not affected by the resolution of instrument.In this case the fractal dimension can reflect the inherent property of rough surface, which can be used as an accurate characterization of surface roughness.Through the analysis of cleaning mechanism of solid dirt, we find that surface roughness has a great impact on interfacial adhesion.The results show that adhesion force changes with surface roughness, Ra<0.4627μm, adhesion force decreases with the increase of surface roughness; 1.3461μm< Ra <2.9755μm, adhesion force increases gradually; Ra>3μm, adhesion force remains the same.Adhesion force also changes with fractal indicator, it changes the opposite trend with surface roughness.

Key words: surface, fractals, fouling, interface, adhesion