(37b) Erosion Model Development for High Concentration Slurry Flow Applications

Computational fluid dynamics (CFD) combined with the discrete element method (DEM) has been used to solve solid particle transport problems for over two decades [1], but only recently the development has been shifted to focus more on liquid slurry flows[2] due to the scarcity of published data and the difficulty in handling high concentration solid flows both experimentally and numerically. This talk will present the development of erosion models using the CFD-DEM approach because of many upstream flow assurance needs, especially in the oil sand operation and hydraulic fracturing.

In contrast to low concentration solid flows, the particle interactions cannot be ignored under high solid concentrations. The commonly used DPM model that ignores such interactions can produce unphysical results showing particle concentration exceeding the packing limit and overestimate the erosion rate by a large degree. However, the hybrid CFD-DEM approach can be expensive and tricky due to its computational cost that limits the number of tracked particles. In addition, models for particle/fluid interactions must be used and that adds another layer of uncertainty. DEM method is preferred due to its wide use in gas-solid flows, but its application in liquid slurry flows has been limited. The Eulerian-Granular model based on the kinetics theory has been successfully applied to dense slurry flows recently [3], and it has been shown that it is capable of predicting solid concentration profiles and pressure drops satisfactorily, but it lacks a proper mechanism to capture erosion phenomenon which requires particle tracking methods that can mimic solid flows in high concentration.

Works will be presented that validate the hybrid CFD-DEM approach by correctly modeling the solid concentration profiles and pressure drops as captured by the Eulerian-Granular model. Furthermore, the erosion correlation that often used in the gas-solid flows was fine-tuned to reflect the impact of liquid flows.

References

1. Snider, D. M.: “An incompressible three-dimensional multiphase particle-in-cell model for dense phase flows,” J. Comp. Phys., 170, pp. 523-549, 2001.
2. Tsai, K., E. Fonseca, S. Degaleesan and E. Lake, “Advanced computational modeling of proppant settling in water fractures for shale gas production,” SPE Journal 18, pp. 50-56, 2012.
3. K. Ekambara, R. S. Sanders, K. Nandakumar and J. H. Masliyah, “Hydrodynamics simulation of horizontal slurry pipe flow using ANSYS-CFX,” Ind. Eng. Chem. Res, 48, pp. 8159-8171, 2009.