A new analysis of the turbulent flow of non‐newtonian fluids

Abstract

A new analysis has been developed for the turbulent flow of non-Newtonian fluids. Based on enhanced viscosity effects at the small time and length scales of the dissipative micro-eddies, the analysis predicts a thickening of the viscous sub-layer tending to increase throughput velocity and thus promoting drag reduction. The required flow parameters can be determined directly from rheograms, without employing correlations based on pipe-flow data. The results give good descriptions of flows of fluids with both power-law and Bingham behaviour and explain a number of peculiarities of such flows.On propose une nouvelle mCthode d'analyse des Ccoulements de fluides non newtoniens. Cette analyse est fondte sur I'augmentation de la viscosit6 dans les microtourbillons (Cchelle de Kolmogorov) et permet de pr6dire un Cpaississement de la sous-couche visqueuse. I1 s'ensuit une augmentation de la vitesse d'6coulement et donc une rkduction de la rtsistance due h la friction. Les parametres necessaires h cette analyse peuvent &tre directement obtenus h partir des rhkogrammes, I'utilisation de corrtlations empiriques &ant rendue inutile. Cette m6thode a ttt testte avec des fluides de type plastique de Bingham et loi de puissance; elle permet de dCcrire avec rkalisme le comportement des fluides ainsi que d'expliquer certaines de leurs particularitks.he flow of non-Newtonian fluids is reasonably well-

A comparative study of friction factor correlations for high concentrate slurry flow in smooth pipes

“…• The Wilson-Thomas (1985) and Morrison (2013) models are found to be the best fit models to the experimental data in the range up to 40000 Re. Within this range both the models can be used alternately.…”

“…Another important feature observed is that for a transitional and turbulent regime (Re ≅ 3000-400000), equation (10) has minimum error followed by equation (20) but showed high variability in terms of data representation ( Fig. 2e and Table 1) and show high rate of increment of relative error beyond 40000 Re which likewise is also explained by Wilson and Thomas (1985). Equation (15) failed to predict and shows highest variability and greatest deviation from the experimental data.…”

“…The extent of under-prediction by the Darby-Melson model for turbulent flow is much higher than the over-prediction by the other models except Blasius (1939) and Slatter (1995) model. For turbulent flow in smooth pipes, the Slatter (1995) equation is the least accurate, whereas the Wilson-Thomas (1985) model has the highest accuracy followed by Morrison (2013) and Danish-Kumar (2011) equation. …”

“…3). The Darby-Melson (1981), Wilson-Thomas (1985), Slatter (1995) and Danish-Kumar (2011) developed separate equations for each flow regimes. By combining different formulas (such as Hagen-Poiseuille (1840) with Colebrook equation, and Swamee-Aggarwal (2011) with Blasius (1913), the statistical analysis and comparisons with experimental data were made for all flow regimes.…”

“…The comparisons of the selected equations with the existing experimental results, which are available in the literature, were expressed through MARE, MRE + , MRE -, RMSE, Ѳ, and S. The statistical comparisons were also carried out using MSC and AIC. The analyses show that the Wilson-Thomas (1985) and Morrison (2013) models are best fit models to the experimental data for the Reynolds number up to 40000. Within this range, both models can be used alternately.…”