To improve the sewage removal efficiency of aquaculture tanks， a funnel-type sewage collection device was designed. Taking a dual-channel circular aquaculture tank with bidirectional jet inlet as an example， a three-dimensional two-phase flow field model was established. Based on the verification of grid independence and the effectiveness of numerical methods， the velocity distribution， water flow uniformity index， water circulation energy utilization rate， and the migration law， agglomeration effect， and removal rate of sewage with different densities were studied. The results show that： The funnel can increase the axial velocity gradient of the aquaculture tank， form a central low-pressure circulation， and promote the agglomeration and discharge of sewage. With the increase of inlet mass flow rate， the mixing capacity of the middle and upper water bodies in the tank is enhanced， but the turbulence and secondary flow in the bottom water body are intensified， causing the sewage removal rate to show a "first decrease then increase" trend. Suspended solids are easily driven by water buoyancy and mainly discharged through the overflow outlet， with the removal rate increasing with the flow rate. The migration path and removal rate of medium-density sediments fluctuate significantly with the flow rate. Sediments are dominated by gravity， and excessive flow rate can cause turbulent disturbance， reducing the removal rate.