Flow of large particles through straight and bifurcating pipe flow - experimental study*

Predicting and modelling multiphase flows with high accuracy is of high relevance in many industrial processes. Flow predictions may lead to reduced energy usage, hardware investments and raw material usage and also an increased product quality. Access to experimental results are necessary in order to develop Computational Fluid Dynamics (CFD) models for multiphase flows. 

An interesting flow case is the flow of relatively large particles (d_p / D = 0.2 - 0.4, where d_p is particle size and D pipe diameter) through straight and bifurcating pipe flow. Experiments in laminar and turbulent flow at different Stokes numbers (1 - 300) and particle to fluid density ratios (0.9 - 1.2) are conducted. Spherical and cubical particles have been compared at volume fractions 5 - 30%. Measurements are performed in a circulating loop and results include pressure drop and velocimetry for the straight pipe flow and particle and fluid distribution in the different branches for the bifurcated flow. Velocity and turbulence statistics are measured using Magnetic Resonance Velocimetry (MRV). Differences between spherical and cubical particles are reported and show under what circumstances it becomes critical to include particle shape in CFD modelling.