Abstract: Dean vortex and spiral flow are a common turbulent vortex structure in the pipeline. Although the two types of vortex have similar functions such as heat and mass transfer, the Dean vortex is prone to cause pipeline system oscillation, which is a great threat to the safety of pressurized water pipeline system. In this paper, the bend pipe system with pipe diameter D=50 mm and radius of curvature 2.8 D is established by the previous physical model test, and the mathematical model is verified based on the test data. The model pipe section is designed with 27 combinations of guide sheets to form spiral flow, and the multi-scale vortex structure in the pipe is simulated, the flow velocity, pressure and turbulent energy distribution of the vortex in the bend and outlet straight pipe are mainly analyzed. The simulation results show that the pipeline system is affected by the turbulent energy of the vortex and the intensity of the turbulence to varying degrees, the bent pipe system has a higher water transfer capacity under conditions of higher turbulent kinetic energy and lower turbulent intensity. Spiral flow strength has a significant impact on the water transfer efficiency of the bend and the safety of the pipeline system. When the pipe inlet flow velocity V=1.5 m/s, the water transmission efficiency of curved pipe system is increased by 10.62% and the probability of pipeline accident is reduced by 24.41% under the action of guide sheet（number N=8, height H=15 mm, deflection angle θ*=60°）. The research results can provide a technical guidance for the long-distance spiral flow conveying theory and pressurized pipeline system optimization.