NUMERICAL AND EXPERIMENTAL STUDY OF HYDRAULIC RESISTANCE OF TUBES WITH INTERNAL HELICAL FINNING BY DEFORMING CUTTING

Abstract

An object of investigation is a tube having helical fins on the internal surface and different geometric sizes. Investigation methods: experiments to obtain quantitative results hydraulic resistance of tubes with internal helical finning and to verify computational algorithm; numerical simulation to visualize the flow structure in the tube. Studies of hydraulic resistance of tubes with internal helical finning over a wide range of operating and geometric parameters were made: ReD=2⋅103...2.5⋅105, under the variation of the angle of swirling a = 14–87°, the relative height of a protrusion h/d = (25–87,5)⋅10–3, the relative axial pitch p/d = 0.16–12.73. It is revealed that the hydraulic resistance of tubes with helical finning increases by a factor of 1.1 to 11.7. The numerical simulation results showed that, as the angle of helical swirling is increased, in the near-wall layers the share of the circumferential velocity component increases and the share of the longitudinal component decreases. And since the finning height exceeds the boundary layer thickness, the hydraulic resistance grows.