Experimental characterization of dynamics of bed-scale liquid spreading in a trickle bed

We report measurements performed to understand the effects of gas (Q_G) and liquid (Q_L) flow rates, surface tension (σ_GL), liquid viscosity (μ_L), and particle diameter (d_p) on dynamics of local liquid spreading, pressure drop, and overall liquid holdup in a pseudo-2D trickle bed. We show that an increase in the gas-phase inertia leads to a decrease in the lateral liquid spreading, whereas an increase in the liquid-phase inertia leads to an increase in the lateral liquid spreading. We also show that an increase in d_p causes a reduction in the lateral liquid spreading. Using dimensionless numbers (AB and We), we propose a regime map showing contributions of different forces to the local liquid spreading. We show that the interplay between the inertia and capillary forces governs the liquid distribution near the inlet, whereas the relative contribution of gravitational force increases toward the outlet. Finally, we propose a relation between AB and We for “bed-scale” liquid spreading.