On the agglomeration and breakage of particles in turbulent flows through pipe bends using CFD-PBE
Kasper Gram Bilde, Jakob Hærvig, Ronald Lehnigk, Fabian Schlegel, Kim Sørensen
Abstract
Predicting the agglomeration and breakage of solid particles is important when designing a compact and efficient water purification process. A coupled computational fluid dynamics model is presented where the population balance equation is applied to track the particle size distribution for a periodic turbulent pipe flow with 180° bends for fluid Reynolds numbers of 15,000<Ref<35,000 and pipe bend radii of rB=dh,rB=1.5dh and rB=2.5dh. The critical parameters in the Euler-Euler model are analysed and values are chosen to describe the agglomeration of soot particles based on an experimentally obtained particle size distribution measured using a Malvern Mastersizer 3000. It is concluded that the particle Sauter mean diameter converges to a constant value independent of the pipe bend radius when Ref>30,000. The Sauter mean diameter increases from d32=42.7μm to d32=95μm without changing the total length of the static flocculator by choosing rB=dh and Ref=15,000.