OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Fig. 5. The effect of turbulence models Fig 6. The effect of Csep GEKO coefficient Fig. 7. The effect of Cnw GEKO coefficient at Csep 1.75 Fig. 8. The effect of Cjet GEKO coefficient at Csep 1.75 and Cnw 0.5 where E90 is the reference erosion rate at a particle incidence angle of 90°; V is the particle velocity; Vref is the reference velocity; d is the particle diameter; Dref is the reference diameter; k2 and k3 are the model coefficients; f(γ) is a function of angle defined as: ( ) 2 1 ( ) (sin ) 1 (1 sin ) , n n f Hν γ = γ + - γ (4) where g – represents the angle of incidence of the particle (in radians); Hν denotes the Vickers hardness coefficient (in GPa); n1 and n2 are constants. DNV model is formulated as: ( ), n P p E m KU f = α (5) where P m is erodent mass flow rate; K, n are constants; 1 ( ) 1 180 i i i f A + απ α = - ∑ , and its coefficients are presented in table 1. The coefficients of empirical-analytical models are dependent on the material and experimental conditions. In order to examine the independent parameters of the Oka model, the coefficients were established
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