Large eddy simulation of particle behavior under two-phase impinging jet erosion

This work aims to study the working mechanism of gas–solid impinging jet erosion leading to specific wall shape as “W” or “U” through large eddy simulation (LES) coupling with particle Lagrange tracking method. The flow characteristics, particle behavior and erosion morphology caused by three-sized particles (St = 1.56, 14.08, 306.73) in the two-phase impinging jet flows were studied comprehensively. Compared with small particle, large particle tends to have higher normal component of the particle–wall impact velocity but lower radial component. Larger particles tend to have more uniform distribution and smaller particles tend to have closer distribution to the wall. Particularly, it is found that small particles tend to generate W-shaped wall and large particles tend to generate U-shaped wall. Impinging on the W-shaped wall, particles near the wall as well as the central axis are less affected by the normal deceleration from the local flow, which leads to high velocity of particle–wall impact. However, particles far away from the central axis are significantly suffered from the normal deceleration from the local flow, which leads to low velocity of particle–wall impact. Compared W-shaped wall with the flat wall, particle distribution is more uniform in the normal direction, less distribution near the wall and more distribution away from the wall. On the other hand, impinging on the U-shaped wall, the inner annular high-vorticity region becomes wider and more concentrated, while the outer annular high-vorticity region becomes sparser and more dispersed. Particle-wall impact velocity at the U-shaped-wall bottom is smaller than that at the flat wall excluding that occurred at the lateral marginal area. Compared U-shaped wall with the flat wall, particle distribution is more even and the maximum of N/N₀ is closer to the center axis.