Experimental and numerical investigation of the hydroerosive grinding

This paper presents an Euler–Euler approach for the numerical simulation of the hydroerosive grinding (HE) process. It describes a two-phase slurry flow consisting of a liquid and a dispersed solid phase which causes wear at walls of devices. The continuous fluid phase is solved using a finite volume scheme in which the Large Eddy Simulation (LES) [1] model is applied to resolve large-scale turbulent structures. The solid phase is dispersed and treated as a second continuum in which drag and lift forces as well as added mass, pressure and history force are taken into account. Considering particle–particle interactions, the granular model from Gidaspow [2] is used for particle volume concentrations over 1%. Investigations of erosion processes proofed that non-spherically shaped particles as well as harder particles increase the wear on devices significantly. Consequently, non-spherical particles are utilised for the hydroerosive grinding. Their steady drag, unsteady drag and lift coefficients, depending on the particle Reynolds number, are determined by a direct numerical simulation via an in-house LES Lattice-Boltzmann solver. This Lattice-Boltzmann method was presented for laminar flows by Hölzer and Sommerfeld [3]. In this work, interpolating functions of these coefficients are implemented in the Euler–Euler approach which enables the simulation of non-spherical particle transport. Hydroerosive grinding experiments in 3D throttles and 3D planar geometries are carried out to determine an erosion model depending on particle impact velocity, particle size, particle concentration and wall hardness. Implementation of a mesh-morphing algorithm combined with the Euler–Euler scheme of the commercial solver ANSYS CFX11 [4] enables an online simulation of the hydroerosive grinding process. Additionally, the online simulation is used to validate the applied numerical methods. Very good agreements are achieved and will be presented in this paper.

An Euler-Euler approach for the numerical simulation of hydroerosive grinding is presented, which describes a two-phase slurry flow causing wear at walls of devices. For the validation of the developed erosion model depending on particle impact velocity, particle size, particle concentration and wall hardness, hydroerosive grinding experiments in different geometries were conducted. The agreement between experiment and simulation was found to be excellent.Figure optionsDownload as PowerPoint slideHighlights
► Development and validation of an Euler-Euler approach for predicting hydroerosive grinding by non-spherical particles.
► Extension of fluid dynamic forces acting on non-spherical particle based on Lattice-Boltzmann simulations.
► Development of an erosion model accounting for particle impact velocity, particle size, particle concentration and wall hardness.
► Experiments obtained for the erosion process in 3D throttle and 3D planar geometry showed good agreement with calculations.
► A parametric study demonstrates the importance of the different conditions on the erosion process.