Numerical Simulation And Experimental Research On Discharge Capacity Of Spring Full Lift Safety Valve

Safety valve is the necessary safety accessories of boiler, pressure vessel and pressure piping. But the safety valve could appear all sorts of fault in the process of work, such as setting pressure deviation occurs, sealing surface is not flat, spring stiffness is high or softening, valve stem isn’t in the center, leading to serious consequences. Even if safety valve normally acts as overpressure, if discharge capacity is insufficient to decompression or overpressure and blow down pressure couldn’t keep balance, will cause serious consequences. Therefore, the research of the safety valve performance evaluation technology is particularly important.The article studied performance assessment technique of safety valve opening process by numerical simulation method, fixed lift and transient open test verified the simulation accuracy, main content as below:Firstly,numerical simulation of safety valve dynamic open and fixed lift were carried out by CFX, using Pro/E 3D basin modeling, structured grids, CEL dynamic grid and so on, and the correctness of the simulation is verified by the test data.Secondly, qualitative and quantitative analyzed two simulation methods for thr first time, finding the difference is small in stable discharge stage, but relative deviation of the performance parameters is bigger in the opening stage;Thirdly,detailed quantitative and qualitative analysis of safety valve supersonic critical flow were carried out for the first time, finding the critical flow presented regular change with the increase of stable lift, and this change was basically not affected by working condition and safety valve specification. Quantitative calculation and analysis of the throat and shade discharge capacity was conducted, got discharge capacity calculation method of different lifts with actual discharge capacity.Fourthly,Studied the relationship between discharge capacity and lift, obtained the fitting formula between different conditions and specifications of the safety valve discharge capacity and stable lift, as well as discharge capacity of stable phrase with lift in open phrase under different working conditionst, achieved the method of assessing discharge capacity by lift;Finally, different steady lifts of safety valve fully open emission test in the same working condition was conducted through the spacing device for the first time.Parameters of the displacement, stress, lift force in safety valve open discharge process were tested by detecting element such as displacement, valve core,the lift and pressure sensor, and compared with the corresponding simulation result, finding that simulation result fit well with test value, verified the accuracy of the simulation. Different steady lifts of discharge capacity measured in experiment verified high precision of the discharge capacity fitting formula, preliminary realized rapid assessment of the safety valve discharge performance, has practical application value.