Gas Leakage Dynamic Study Of Lift Coefficient During Opening Process Of Safety Valve

As a safety device to prevent overpressure,the fully-open spring safety valve is widely used in petrochemical,nuclear power and other fields.Its main performa nce indicators include rapid opening and timely discharge.From the dynamic characteristics of the safety valve,it can be seen that the spring,recoil plate and sealing surface structure of the full-open safety valve have an important influence on the rapid opening of the safety valve.In this paper,the influence of structural parameters on lift coefficient during the opening process of safety valve is analyzed by theoretical analysis and dynamic mesh UDF transient numerical simulation method.At the same time,the lift force of the dynamic opening process of the fully open spring safety valve was tested and verified with the numerical simulation results.The main research contents of this paper include :The transient flow field simulation of the full-open spring safety valve was carried out by using Fluent software dynamic grid UDF programming technology,and the results were compared with the steady-state simulation results to analyze the errors and causes.Using the theoretical formula,the characterist ic curve and lift coefficient curve of the full-open spring safety valve are drawn.The safety valve test bench was built to test the opening process of A42Y-64 fully open spring safety valve online,and the lift,opening height and opening speed of the safety valve were obtained.The relationship between the experimental data and time is analyzed,and the numerical simulation results are compared with the experimental results to verify the accuracy and feasibility of the transient numerical calculation method.The force of the upper and lower surfaces of the recoil plate and the valve core is analyzed.By studying the influence of the convex angle of the recoil plate and the diameter of the recoil plate on the lift,recoil force and lift coefficient,the st ructure of the recoil plate is optimized.The influence of the chamfering of the outer edge of the valve core sealing surface and the chamfering of the inner edge of the valve seat sealing surface on the lift and lift coefficient was studied.The influence of chamfer position and size on the opening process of safety valve is compared and evaluated.