A general correlation for turbulent friction factors in non-Newtonian fluids

TL;DR

This paper introduces a universal correlation for turbulent friction factors in non-Newtonian fluids that does not depend on specific rheological models, matching existing accuracy and improving profile visualization.

Contribution

It presents a new empirical correlation for turbulent friction factors applicable to all purely viscous non-Newtonian fluids without assuming a rheological model.

Findings

Matches accuracy of Dodge-Metzner correlation

Provides better visualization of velocity profiles

Easily adaptable to specific rheological models

Abstract

Correlations of friction factors are presented for the general case of purely viscous non-Newtonian fluids without requiring a priori the adoption of a rheological model. They are based on an empirical estimate of the shift in the wall layer edge and the Kolmogorov point. The predictions of friction factors have the same level of accuracy as those of the Dodge-Metzner correlation but the visualisation is more compatible with measured velocity profiles. The general correlations obtained can be used to easily retrieve correlations for specific rheological models.