Abstract The efficient and safe discharge of powders from multi-outlet silos is critical in many industrial processes. This study applied a two-fluid model to investigate powder-gas dynamics in a dual-outlet silo with outlet diameters of 0.26–0.78 m. Results show that larger outlets accelerate subsidence of the free surface, deepen local depressions, and significantly raise particle velocities, leading to expansion of rapid-flow regions near the outlets. The powder volume fraction exhibits a W-shaped profile in the upper silo and a V-shaped distribution close to the outlets, reflecting the combined effects of gravity and silo geometry. Negative pressure zones consistently emerge above the outlets during early discharge; increasing outlet size not only amplifies these pressure peaks but also promotes faster recovery. Moreover, slight competitive effects between the two outlets were identified, indicating interaction in discharge pathways. These findings demonstrate that outlet diameter is a critical parameter governing both flow dynamics and discharge performance in dual-outlet silos.
Liu et al. (2026) studied this question.