Study On Influence Of Different Duide Vane Angled Cyclone On Flow Velocity Characteristics Of Spiral Flow In Downstream Section

The sand discharge and sediment reduction work in the water conservancy project is an important measure to maintain the good operation state of the reservoir.In order to improve the efficiency of sediment transport of the sediment transport pipeline,a measure of spiral flow and discharge of the circular pipe is proposed,which mainly passes through the pipeline.The method of providing a guide vane to generate a spiral flow to transport sediment is characterized by high efficiency and energy saving.In this paper,the combination of physical model test and numerical simulation is used to study the flow velocity characteristics of the spiral flow downstream of the cyclone.The main research contents are: the distribution of the three-dimensional flow velocity of the downstream section of the cyclone;the variation of the circumferential and radial flow velocity along the downstream section of the cyclone;the maximum circumferential velocity of each section downstream of the cyclone The trend of change analyzes the attenuation law of the downstream spiral flow;the influence of the wrap angle of the swirler vane on the cross-section distribution of the three-dimensional flow velocity of the downstream section and the variation along the path;the influence of the flow rate on the flow velocity characteristics of the spiral flow downstream of the cyclone.The main conclusions are as follows:(1)The axial velocity,circumferential velocity and radial velocity distribution of the entire section downstream of the cyclone are symmetrically distributed with respect to the center of the section at 120°.In the section near the trailing edge of the vane,the axial velocity near the vane is a minimum value on the concentric ring of the section,and the distribution of the axial velocity along the polar axis near the wall is smoother than that of the tube.The circumferential velocity near the center of the section near the trailing edge of the vane is counterclockwise,the circumferential velocity near the wall is clockwise,and the circumferential velocity in each direction increases from the inside of the pipe to the wall along the polar axis.The trend of decreasing after large,the clockwise circumferential velocity is greater than the counterclockwise circumferential velocity;the radial velocity distribution of the section is deviated from the center of the section and the centripetal velocity is staggered according to the same size of the sector,divided into six regions.,along the polar axis from the center of the pipe to the pipe wall first increased and then decreased;radial velocity is less than the circumferential velocity,the circumferential velocity and radial velocity tend to zero at the center of the pipe and the pipe wall.(2)As the spiral flow develops downstream and gradually decays,the three-dimensional velocity distribution area of the section will rotate in a clockwise direction,and the axial velocity of the section will gradually concentrically distribute,and the axial velocity distribution along the polar axis will tend to Logarithmic distribution;the circumferential velocity of the section gradually spreads to the full section,and the circumferential velocity decreases gradually;the radial velocity of the section is gradually smaller.(3)The larger the guide vane wrap angle,the axial velocity near the downstream wall of the cyclone is more gradual along the polar axis,and the difference is not obvious in the section far from the trailing edge of the vane;circumferential and radial velocity Bigger.(4)The circumferential velocity and radial velocity of the characteristic points near the wall of the downstream section of the cyclone gradually decrease in the form of waves,and fluctuate significantly before 2m from the trailing edge of the guide vane.(5)From the analysis of the variation of the maximum circumferential velocity of the section,it can be seen that the spiral flow downstream of the cyclone attenuates faster before 2m from the trailing edge of the guide vane,and then the attenuation is slower.The section position near the trailing edge of the guide vane is 5m.The circumferential velocity tends to zero and the spiral flow disappears.(6)The large guide vane wrap angler produces a stronger spiral flow downstream,which has a longer influence on the downstream water flow,and the strong spiral flow is attenuated faster in the pipe section closer to the trailing edge of the guide vane.(7)Increasing the flow rate,a stronger spiral flow downstream of the cyclone,but the increase in the influence distance is not obvious.The research results of this paper have certain reference value for enriching the spiral flow theory of circular tubes.