Effect of wall roughness on particle deposition on the outer wall of the vortex finder in a cyclone separator

Aiming at the coking caused by particle deposition in cyclone separators in residue fluidized catalytic cracking, the effects of wall roughness on particle deposition characteristics on the outer wall of a vortex finder in a cyclone separator based on experiments and numerical simulations. As well, the area of a reverse pressure gradient, tangential velocity, the boundary layer and force are discussed. [Display omitted] •Effect of wall roughness was investigated on particle deposition of the cyclone.•The amount and distribution of deposited particle were quantitatively analyzed.•The non-particle deposition zone was reduced due to enhancement of secondary vortex.•Boundary layer was growth because of expanded area of a reverse pressure gradient.•Saffman force plays a crucial role in the flow field and forces on fine particles. The influence of wall roughness on particle deposition in residue fluidized catalytic cracking cyclone separators have so far been ignored. This study investigates the effects of wall roughness on particle deposition characteristics on the outer wall of vortex finder in cyclone separators based on experiments and numerical simulations. The results indicate that mass and median diameters of deposited particles increased as roughness increased. Additionally, reduced no-particle deposition area on the outer wall of vortex finder due to wall roughness. In the context of increased roughness, deposited fine particles were mainly influenced by expanded area of a reverse pressure gradient, reduced tangential velocity and flow shear near the wall, and growth of the boundary layer. The study shown that Saffman force played a crucial role in this phenomenon. The results described herein provide a theoretical foundation for understanding particle deposition in cyclone separators and offer valuable insights for improving performance.