On the agglomeration and breakage of particles in turbulent flows through pipe bends using CFD-PBE

Particle agglomeration and breakage through pipe bends in turbulent flows are important for a wide range of industries and applications. A computational fluid dynamics (CFD) model is presented where the population balance equation (PBE) is applied to track the particle size distribution for a periodic turbulent pipe flow with 180◦ bends with a fluid Reynolds number in the range 15, 000 < Ref < 35, 000 and for three different pipe bend radii of rB = 1dh, rB = 1.5dh and rB = 2.5dh. The critical parameters in the Eulerian framework are analysed and suitable parameters are chosen to describe the agglomeration of soot-like particles suspended in water based on an experimentally obtained particle size distribution. The experimental particle size distribution of flocculated
soot particles was measured using a Malvern Mastersizer 3000 at the outlet of a static flocculator with a bend radius of rb = 1.5D. It is concluded that for the particle properties applied, the particle Sauter mean diameter converges to a constant value independent of the pipe bend radius when the fluid Reynolds number exceeds Ref = 30, 000. The agglomeration and breakage kernels for solid particles in a turbulent fluid flow are implemented in the open-source CFD library by the OpenFOAM Foundation.