4229 円管内での高レイノルズ数気体の長時間拡散挙動について(G05-14 管内流・旋回流,G05 流体工学)  [in Japanese] 4229 Long-time Diffusion Behavior of Gas with High Reynolds Number in a Pipe  [in Japanese]

The heat rate of a gas in a pipe was measured 50km away from a point where that changed in a step in order to investigate the effect of the axial turbulent diffusion on the concentration. Reynolds No. ranged from 3.8e6 to 5.8e6. From this measurement, it has been proved that the concentration spatial distribution due to the axial turbulent diffusion is not influenced by Reynolds No. in case where the difference in Reynolds No. is not large. The non-dimensional diffusivity C was determined to be 17 as means of the curve-fitting. It has been concluded that the use of alleged C=10 leads to smaller diffusion.