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영어

Experiments were carried out for the turbulent swirling flow and heat transfer characteristics of an eccentric expansion in a circular tube with a constant heat flux. The uniform heat flux condition was imposed to the downstream of an eccentric expansion by using an electrically heated tube and the flow upstream of the expansion was unheated and fully developed. experimental data are presented for local axial velocities and local heat transfer rates in the tube downstream of an abrupt 3:1 expansion. Air was used as the working fluid. In the upstream tube, the Reynolds number was varied from 4*104 to 10*104 and swirl number range(based on the swirl geometry, I.e., L/d ratio) in which the experiments were conducted was L/d = 0, 10. The results obtained are summarized as flows. 1) Fully development region showed from x/d=22 to downstream in case of non swirl flow but x/d=30 on the swirl flow 2) The wall temperature and the bulk temperature showed high when Reynolds numbers was small and swirl intensity was increased. 3) The location of the maximum NU/NUDB showed at the point of 4 step hights, for Re=6*104. 4) Reattachments