The results of numerical study of fully developed turbulent flow in a circular cross-section helicoidal pipe with finite pitch are reported in this paper. The k-ε model is used to model the turbulent behavior. The time-average momentum, as well the k and e equations, have been derived in the helicoidal coordinate system. The results indicate that the secondary flow exhibits a two-vortex pattern in the cross section. As torsion is applied, the two vortices become asymmetric, and the distortion is proportional to the dimensionless torsion. The results also indicate that the torsion effect on the turbulent helicoidal pipe flow is not as significant as in the case of laminar flow. When dimensionless torsion increases from 0 to 0.5, and Re is around 6.8×10{sup}5, the flow rate in the turbulent flow will increase almost 4%, and fRe reduces to almost 3%. A previous investigation showed that fRe will reduce around 19% for laminar flow when Re = 400, and for the same changes in torsion.
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