Numerical investigation of erosion on a staggered tube bank by particle laden flows with immersed boundary method

In the present paper, particle-laden flows past 10 × 11 staggered stainless steel tube banks in a duct and the caused erosion are investigated using point-particle Eulerian–Lagrangian method. The continuous gas flow field is obtained through direct numerical simulation. The coupling between fluid and the embedded tubes is handled through the multi-direct forcing immersed boundary method. Four types of coal ash particles with Stokes numbers 0.01, 0.1, 1.0, 10.0, are considered. The collision and erosion characteristics on the tubes located in the middle of the duct are analyzed in detail. It has been found that the global tube erosion of the first tube increases with the increment of the particle size, but particles with an intermediate Stokes number of 1.0 cause the most erosion to the other downstream tubes due to preferential accumulation effect. Results predict much more erosion to the second row of tubes in staggered tube banks than the first row of tubes. Global erosion to the tubes near the wall is much larger than the corresponding ones located in the center, especially far downstream. The maximum local tube erosion occurs within certain angle regions around the tubes, where more attention needs to be paid to prevent erosion.