Dynamic Simulation Of Two-phase Flow Field Of Floating Valve Tray Under Wind Load

The float valve tower is one of the most common production equipment in chemical industry.As a moving part of the float valve tray,the float valve opening is automatically adjusted with the gas phase load.However,in recent years,the traditional research on the floating valve tray is the research under the maximum opening,not the dynamic process,and does not consider the changes of tray flow field under different liquid velocity or different gas velocity and the influence of additional load(including wind load,seismic load,etc.)on it.Under the actual working condition,the influence of wind load on the flow field of tray can not be ignored.In this paper,combined with the wind load factors,the gas-liquid two-phase flow field on tray is simulated.First of all,the whole model of the floating valve tower is established,the model is meshed by ICEM,and the modal analysis is carried out by ANSYS Workbench,and the natural frequency and natural period of the floating valve tower are obtained.Secondly,the numerical wind tunnel method is used to establish the overall wind tunnel model of the floating valve tower.The external flow field,crosswind amplitude and downwind amplitude of the floating valve tower are obtained,and the physical model of the floating valve tower plate is established.In order to ensure the accuracy of the model,the grid independence and clear water height of the valve tray model are verified.Finally,the dynamic grid technology is used to simulate the gas-liquid two-phase flow field on the floating valve tray and the vibration of the tray under the wind load.By monitoring the dynamic opening process of the float valve,it is found that there is a protuberance phenomenon of "liquid package" near the overflow weir,and the reverse flow phenomenon of liquid phase occurs at the overflow weir.The volume fraction,velocity distribution and flow characteristics of gas and liquid on the tray vary with the inlet gas velocity or liquid velocity.It is also found that the liquid velocity changes with the opening of float valve,and in the process of continuous change,the liquid velocity shows an upward trend.The number and arrangement of floating valves also directly affect the flow field distribution on the tray.In the simulation of downwind tilt of tray,it is found that the different tilt direction of valve tray will have an uneven impact on the velocity distribution,and with the tray tilt,there are jet and wall flow phenomena at the downcomer.In the simulation of transverse periodic vibration,it is found that the periodic vibration of floating valve tray directly affects the velocity distribution,liquid level height,volume fraction and other factors.Through data monitoring,it can be concluded that in a complex vibration period,due to the constant change of the vibration direction of the tray and the lag of the liquid flow,the gas-phase velocity also fluctuates,which shows the phenomenon of acceleration first and then deceleration,but in the whole vibration period,the gas-phase velocity increases.