OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 a local region of flow acceleration forms, flowing around the braking region. The heterogeneous flow accelerator creates a high-velocity jet, which promotes the downstreamairflow’s ejection and its acceleration. As a consequence, a zone of opposing currents is created, which has no impact on the erosion process anymore, given its significant distance from the eroded surface (refer to fig. 4, located at the base of the high-velocity jet, in the center). Fig. 4. High-velocity flow impacting sample surface To construct an erosion rate analysis and develop model comparisons, we utilised the specific erosion wear criterion which was determined by calculating the ratio of mass that was removed to the mass of particles present in each cell on the sample surface (specifically region 4.1 in fig. 3). The turbulence model’s impact along the length of the sample, on the radius of the wear spot is shown in fig. 5 (where the centre of the spot is identified as 0 mm). The limited effect of the turbulence model is evident, which is caused by the similar distribution of flow velocities and turbulent viscosity (which is determined by the turbulence model), as shown earlier for the reacting flow [32]. As previously mentioned, the GEKO model provides unique opportunities to adjust the model coefficients. Figs. 6–8 demonstrate the effect of the GEKO model tuning parameters – Csep, Cnw, Cjet. It is apparent that the primary adjustment coefficients of the GEKO model have minimal or no impact on erosion wear when varied within a broad range, even when compared to the overall influence of the turbulence model. The impacts of the erosion model were evaluated using two of the most widely used models, Oka [30, 34] and DNV [30, 35]. The Oka model was utilized through the following formulation: 2 3 90 ( ), k k ref ref V d E E f V d = γ (3)
RkJQdWJsaXNoZXIy MTk0ODM1