Numerical study on characteristics of particle deposition efficiency on different walls of 90° square bend

Abstract

A better understanding of the characteristics of particle deposition in bend would help in designing a sampling bend. In this paper, gas-solid flow in 90° bend was simulated using the RNG k-ɛ turbulence model and the Lagrangian particle-tracking model. The preliminary results show that the deposition efficiency in 90° square bend is lower than that in 90° circular bend. Afterwards, the flow field, particle trajectories, and effect of curvature ratio on deposition efficiency on different walls were analyzed in 90° square bend. The results show that the main deposition location is related to the Stokes number. On inner wall, the deposition efficiency increases first and then decreases as the Stokes number increases, and particles mainly deposit in middle deflection angles range. Moreover, increasing the curvature ratio changes the flow field in the bend and, in turn, the deposition efficiency on inner wall and distributions of deposition efficiency on outer wall.