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采用有限体积法,对多尺度分形柱群结构的流动换热进行了二维瞬态数值模拟.本文针对呈Sierpinski地毯配置,详细研究了多尺度分形柱群结构和均匀圆柱群内的流动换热,并做了比较分析,研究表明:在分形结构中,流体流动流线呈现弯曲和自相似的特征.分形圆柱群与方柱群的系统努谢尔数随雷诺数的变化趋势基本类似,但是分形圆柱群换热性能较好.同时将分形柱群系统努谢尔数拟合为雷诺数的幂函数,结果显示,随着分形柱群级数增加,雷诺数的指数逐渐增大.四级分形柱群的努谢尔数与雷诺数近似成线性关系.本文的研究可帮助进一步了解多尺度中换热的机理.“,”Unsteady flows passing a multi-scale fractal structure were simulated using the finite element method.Convection heat transfer process around Sierpinski carpet,a kind of fractal structure,is carefully studied and discussed.Both square cylinders and circular ones are investigated in detail.The crooked streamlines past these kinds of fractal structures are shown self-similar approximately.For the relation between Nusselt number and Reynolds number,the circular cylinders show same trend with that of square cylinders.It is found that the heat transfer performance of the circular cylinders is better than that of square ones owing to larger heat exchange area.The empirical dimensionless correlations for different fractal structure is fitted successfully,which indicate that the Nusselt number is a power function of Reynolds numbers.The exponents of correlations increase with the fractal degree.Linear correlation at the forth degree is obtained,which means good heat exchange performance of multi-scale structure.This research would be helpful to understand heat exchange mechanism for the multi-scale structure well.