OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 phenomenon. Many empirical-analytical methods were developed to estimate engineering erosion rates. These include the Finnie, Bitter, Oka, Tabakoff approaches, among others. These methods were applied and continuously improved over time. Recently, numerical modelling methods using both CFD (computational fluid dynamics) and FEA (finite element analysis) as well as SPH (smooth particle hydrodynamics) and its derivatives, which allow for the study of micro-level processes [1, 9–14], have made significant progress. Previously, the text provided a brief overview of erosion modeling methods, examining some works that applied CFD and FEA [8]. One of the most commonly used methods for modeling and verification is a system comprising one or more 90° bent channels that accelerates particles using a carrier phase, typically air, which in turn erodes the surface [2, 3, 15]. When modelling particle motion using CFD, the EulerLagrange approach is commonly used to depict particle groups as mathematical points with known mass, material and dimensions [16–18]. In publications, authors compare and suggest various turbulence models, with calculations typically based on the Reynolds-averaged Navier-Stokes equation system, alongside semiempirical erosion models, depending on the specific issue. Shinde et al. [1] conducted an excellent review of the use of CFD and empirical-analytical models. The authors establish that CFD has a high level of accuracy for various issues and note the need for new empirical-analytical relationships and estimating particle angle of incidence, which relies on carrier phase. The findings regarding erosion wear caused by particles in fluid flow that cannot be compressed, known as “slurry erosion”, are relevant to erosion in a gaseous medium as well. Therefore, the E/CRC group’s representatives, H. Arabnejad [19] and A. Mansouri [20], have created and confirmed empirical-analytical connections by separating the types of wear: deformation and abrasion, which was previously suggested by Bitter [6, 7]. These models involve numerous parameters, covering aspects such as particle shape, flow conditions, and surface material. Overall, these relationships hold great potential for modelling erosion in gaseous media. The contemporary examination of erosion by particles involves FEA and SPH modelling. This approach was scrutinized in multiple reviews, including those by R. Tarodiya and A. Levy, A. Krella, V. Bonu and H. Barshilia, A. Fardan [9–12]. Modern works are focused on refining material models that describe plastic behavior and fracture conditions, as well as the influence of sample temperature, coatings effectiveness, particle shape and size. Additionally, these works also take into account the conditions of particle flow, including velocities, mutual collision, angles of incidence, and particle rotation. This became possible due to the ability to model particle-surface collisions explicitly [21–28]. Despite significant effort to develop a methodology for modelling the erosion caused by solid particles on different materials and under various conditions, there is currently no universally applicable methodology to describe both micro- and macro-level processes. However, ongoing studies examine specific phenomena and the impact of mathematical models on material erosion in particular cases. This paper is focused on the modelling of surface erosion in a popular titanium alloy (Ti6Al4V) caused by SiO2 particles flowing in air. Accurate gas flow description is crucial in this modelling process, particularly when using the most common Reynolds-averaged Navier-Stokes equations (RANS) approach that requires the selection of a turbulence model. CFD erosion modelling involves estimating the surface material entrainment rate as a function of particle impact conditions. Typically, empirical-analytical methods are used, relying on empirically-based coefficients for a narrow range of conditions. These coefficients may require adjustment, and it is necessary to evaluate the model sensitivity to its variation. Many studies analyzed the impact of turbulence models in CFD modelling of the particle erosion process. However, most of these studies were conducted at low velocities of heterogeneous mixture flowing on the surface (less than 150–200 m/s) and did not incorporate the relatively new generalized equation k-omega (GEKO) model [29–31]. The model can be calibrated using multiple coefficients to mimic a particular issue while sustaining coherence and physicality. In this paper, the GEKO model is analyzed in comparison to the commonly used k-epsilon standard and RNG, with particular emphasis on its unique features. Additionally, current publications primarily examine erosion caused by particles of a singular or limited diameter range. However, considering the non-uniform distribution of particles can significantly affect the
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