Turbulent pipe flow with spherical particles: drag as a function of particle size and volume fraction

TL;DR

This study investigates how particle size and volume fraction affect drag and flow characteristics in turbulent pipe flow with spherical particles, combining experiments, simulations, and modeling to improve pressure drop predictions.

Contribution

It introduces a master curve for drag change that accounts for particle size, enhancing the accuracy of friction factor predictions over traditional viscosity models.

Findings

Particle size and flow rate influence fluid velocity and particle distribution.

Effects of particles diminish at higher flow rates.

Master curve improves pressure drop predictions.

Abstract

Suspensions of finite-size solid particles in a turbulent pipe flow are found in many industrial and technical flows. Due to the ample parameter space consisting of particle size, concentration, density and Reynolds number, a complete picture of the particle-fluid interaction is still lacking. Pressure drop predictions are often made using viscosity models only considering the bulk solid volume fraction. For the case of turbulent pipe flow laden with neutrally buoyant spherical particles, we investigate the pressure drop and overall drag (friction factor), fluid velocity and particle distribution in the pipe. We use a combination of experimental (MRV) and numerical (DNS) techniques and a continuum flow model. We find that the particle size and the bulk flow rate influence the mean fluid velocity, velocity fluctuations and the particle distribution in the pipe for low flow rates. However, the effects of the added solid particles diminish as the flow rate increases. We created a master curve for drag change compared to single-phase flow for the particle-laden cases. This curve can be used to achieve more accurate friction factor predictions than the traditional modified viscosity approach that does not account for particle size.