Particle-resolved CFD study of liquid axial penetration and lateral spreading in an ordered trickle bed reactor

Trickle bed reactors are frequently applied in the chemical process industries for gas-liquid-solid contacting. The performance of these reactors is sensitively influenced by the hydrodynamics. This study focuses on investigating the complex interaction between the gas and liquid phases in these reactors. Specifically, the effects of inlet liquid flux, surface wettability, and gas velocity on lateral spreading and axial penetration of the liquid are explored. An ordered trickle bed is used to reduce the effects of the configuration of the particles on these parameters. Using Direct Numerical Simulation (DNS), we determined that the lateral spreading and axial penetration are enhanced with an increased liquid flux, as expected. Interestingly, the initial liquid inertia, represented by the liquid jet velocity, has limited influence on both lateral spreading and axial penetration in the ordered bed, while the gravitational force is the dominant factor for the axial penetration. Furthermore, the contact angle has minimal impact on lateral spreading, indicating the presence of an additional force restricting spreading. Notably, the gas velocity is identified as a crucial factor influencing lateral spreading, as high velocities prevent the capillary forces from spreading the liquid. These insights in the contributing forces on the spreading behaviour in trickle bed reactors facilitate an improved reactor design and optimization.