Abstract:The desilting channel with a swirling flow is a new technology for separating water and sediment in the channel, which is proposed based on the strong carrying capacity of the swirling flow. To clarify its water-sediment characteristics, the water and sediment two-phase flow in the desilting channel are simulated with realizable k-ε model, VOF method and discrete phase model based on the experimental test. The shape factors of the sediment with different particle sizes are determined by comparison with the model test results. The sediment discharge effect of the desilting channel under the condition of continuous sediment inflow is studied, and the sediment movement characteristics in the channel and sediment transport pipe are analyzed. The results show that, when the shape factors of sediment with different particle sizes is between 0.2 and 1.0, the simulated sediment trapping efficiency of sediment with particle size of 0.075～3.000 mm in the desilting channel with a swirling flow is in good agreement with the experimental value under the condition of local inflow of sediment from the top of the channel. The relative error is only 3.5 % between them, which mainly comes from 0.075～0.160 mm of fine sediment particle size. When the sediment is imported continuously from the upstream channels at a mass flow rate of 60 g/s, the sediment content of the channel decreases rapidly because of the diversion of the swirling flow generator for the hyperconcentrated flow at the bottom of the channel. The sediment content of the channel bottom flow before and after the swirling flow generator is 44 kg/m3 and 0.07 kg/m3 respectively. The swirling flow in the sediment transport pipe has obvious sediment carrying effect, and the sediment is mainly distributed near the wall of the sediment transport pipe under the strong centrifugal action of the swirling flow, where the maximum sediment content is about 200kg/m3. Under the condition of continuous sediment inflow, the sediment trapping efficiency of the desilting channel with a swirling flow is 95.98 % for the particle size of 0.075～3.000 mm. Only a small amount of fine sediment enters the downstream channel in the form of suspended matter, and there is no large amount of sediment deposition in the channel and the sediment transport pipe, which indicates that the desilting channel with a swirling flow is a kind of water and sediment separation technology with high efficiency and continuity. The results can provide a useful reference for the application of desilting channel with a swirling flow in engineering, as well as the study of water and sediment characteristics.