Flow of non‐newtonian fluids—correlation of the laminar, transition, and turbulent‐flow regions

TLDR

Existing data on non‑Newtonian pipe flow have been correlated on the friction‑factor versus Reynolds‑number plot used for Newtonian fluids, yet further work is needed in the transition and turbulent regimes. The study aims to extend this correlation to thixotropic, rheopectic, and dilatant fluids, filling a data gap and providing theoretical and practical insight. The authors tested the correlation on 16 non‑Newtonian materials across a Reynolds‑number range of 6.3 × 10⁻⁵ to 1.3 × 10⁵, using pipe diameters from 1/8 to 12 inches. The correlation is fluid‑type independent and can be applied to both Newtonian and non‑Newtonian fluids.

Abstract

Abstract All available data on flow of non‐Newtonians in pipes have been correlated on the conventional friction factor — Reynolds number plot for Newtonian fluids. This correlation, theoretically rigorous in the laminar flow region, was tested with data on 16 different non‐Newtonian materials covering the 2.1 × 10 9 range of Reynolds numbers from 6.3 × 10 −5 to 1.3 × 10 5 . Pipe diameters varied from 1/8 to 12 in. As the correlation does not depend on the type of fluid encountered, it may be used with Newtonian and non‐Newtonian fluids alike. In spite of the great range of the available experimetnal data, further work is necessary in the transition and turbulent‐flow regions. No data at all were available on thixotropic, rheopectic, and dilatant fluids, and extension of the correlation to these materials should prove most illuminative from both theoretical and practical viewpoints.