Numerical investigation on the similarity of developing laminar flows in helical pipes

This paper presents numerical investigations into the similarity of developing laminar flows at the entrance region of helical pipes. It is shown that the new characteristic parameters can be used to represent the flow development in helical pipes. The development of friction factor and flow pattern along with the characteristic parameters is not significantly affected by the variations of Reynolds number, dimensionless pitch, or curvature ratio at a given condition of modified Dean number and inlet velocity profile. The development of the friction factor is investigated in a modified Dean number range of 20–400, and a new correlation for the fully developed angles of laminar flows in helical pipes is proposed.

► New characteristic parameters and a modified Dean number were applied. ► We confirmed the similarity of developing laminar flows in helical pipes. ► The development of friction factor is investigated in a De+ range of 20–400. ► A new correlation is proposed for the fully developed angles in helical pipes.