Abstract: Fixed-bed reactors are widely used in chemical production, and the shape of the catalyst particles can significantly influence the fluid flow characteristics within the bed. Using a DEM-CFD one-way coupling approach，the fluid flow patterns in catalyst beds packed with spherical, cylindrical, trilobe, and butterfly-shaped catalyst particles were investigated. Results demonstrate that increased inlet velocity induces flow complexity. Vortices were observed in all four types of particle beds, while channeling flow was notably present in beds with spherical and cylindrical particles. The butterfly-shaped catalyst bed exhibited the most uniform fluid velocity distribution. The pressure drop calculated by the Ergun equation showed good agreement with the simulated values for spherical and cylindrical particle beds, but exhibits significant deviations for trilobe and butterfly-shaped particle beds. A modified Ergun model incorporating shape-dependent correction factors achieved prediction accuracy within 5% for trilobe and butterfly-shaped particles. Additionally, the spherical particle bed demonstrated the shortest average residence time, while the cylindrical, trilobe, and butterfly-shaped particle beds exhibited similar average residence times. These findings are expected to provide valuable insights for the optimization of particle structures in fixed-bed reactors.

Key words: fixed-bed, numerical simulation, fluid flow, butterfly-shaped catalyst