Research On The Dynamic Characteristics And Collision Noise Of The Opening And Closing Flow Field Of Axial Flow Check Valves

Axial flow check valve is widely used in petroleum,petrochemical,aerospace,urban construction and other national economic fields because of its advantages of throttling,anti-reverse and good circulation capacity.With the increasingly frequent use of check valves,higher requirements are placed on their operational stability and reliability.The frequent opening and closing of the check valve will cause the valve disc to oscillate,and will also cause damage to the sealing assembly,and even cause impact noise,thus affecting the normal operation of the pipeline.Therefore,In this paper,the axial flow check valve is taken as the research object.Through the combination of theoretical analysis and numerical simulation,the dynamic characteristics and internal flow field changes of the valve during dynamic opening and closing are studied.At the same time,the impact response and collision noise of the valve at the moment of closing are studied experimentally,and the feasibility and accuracy of the numerical method are verified.The research contents are as follows:(1)By discussing the research status of domestic and foreign scholars in valve opening and closing dynamic characteristics,impact response and collision noise,the problems and potential hazards of axial flow check valve in operation are found.At the same time,through the study of check valve flow field,transient dynamics and acoustic theory,it lays a theoretical foundation for the subsequent research objectives.(2)The opening process and dynamic closing process of axial flow check valve are simulated by Fluent software combined with UDF function.Aiming at the phenomenon of valve disc oscillation during opening process,a structural improvement scheme is proposed to reduce valve disc oscillation,and the feasibility of the improvement scheme is illustrated by comparing the difference of valve disc force,opening time and valve disc motion speed before and after improvement.In addition,the influence of different inlet pressures on the dynamic characteristics of the valve is analyzed,and the impact speed of the valve disc at the moment of closing the valve is obtained.(3)The ANSYS/LS-DYNA software is used to numerically calculate the impact problem of the valve disc impacting the valve seat at the moment of valve closing.The stress distribution of the valve disc and the valve seat changing with time during the collision process is studied.The influence of different impact speeds on the sealing surface stress and collision force of the check valve is explored.Finally,the energy loss of the collision process is studied from the aspects of valve disc speed change and system energy conversion.(4)Taking the transient vibration displacement response of the check valve as the boundary condition,the LMS Virtual.Lab acoustic software is used to simulate the collision noise at the moment of closing the check valve.The sound pressure level distribution of the sound field radiated by the collision noise of the check valve and the sound pressure level curve of the monitoring points at different positions on the field point grid in the transient boundary element model are studied.Finally,the influence of impact velocity on the sound field of collision noise is explored.(5)Using the same simulation method as the above research,the collision noise between steel ball and steel plate is numerically simulated.At the same time,an experimental platform was built in a valve detection center to make the steel ball fall vertically into the steel plate in the water supply pipeline.The SDT-270 acoustic detector was used to measure the sound pressure amplitude of the steel ball impacting the steel plate,and the experimental results were compared with the numerical simulation results to verify the reliability and correctness of the numerical simulation method of collision noise in this paper.Through the above research contents,it can provide reference for the numerical calculation of the opening and closing process of the check valve,so as to improve the operation stability of the check valve.At the same time,the research provides ideas and methods for the numerical simulation of the impact response and collision noise of the check valve,which has certain guiding significance for the practical application of the project.