流れ方向に矩形断面突起を有する直円管路内の乱流構造解析

概要

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A numerical analysis has been performed for turbulent flow developing in longitudinally finned tubes. Three tube geometries were calculated : two 8-finned tubes (fin hight to radius ratios of 0.333 and 0.167) and one 16-finned tube (fin height to radius ratio of 0.167). In calculations, an algebraic Reynolds stress model was adopted in order to predict precisely the secondary flow of the second kind induced by anisotropic turbulence and boundary-fitted coordinate system was introduced as the method of coordinate transformation. Mean velocities in axial, radial and circumferencial directions, pressure drop in tubues and primary shear stress distribution are compared with the experimental data. As a result of this analysis, it was found that the present method could predict well the streamwise mean-velocity. In the case of 8-finned tube of tin height-to-radius ratio 0.333, two secondary flow cells which were measured in experiment, were reproduced by the present turublent model although a small intensity of secondary flow were observed compared with the experiment. Moreover, numerical results suggest that these two secondary flow cells disapper in 8-finned tube of tin height-to-radius ratio 0.167 and the secondary flow has a influence on the wall shear stress distribution. The calculated results also show that the turbulence in the interfin region is greatly reduced as well as the experiment.
一般社団法人日本機械学会の論文
1999-03-25