High Temperature And High Pressure Steam Drain Alve Sealing Surface Failure Analysis

The function of steam boiler drum platoon valve is to pour out the unpurified water inthe boiler drum constantly so that it can keep the vapor at a high quality. The sealingsurface of drain valve is easy to ravage under high pressure and unpurified circumstance.To enhance the plant’s economic benefit, it is of great value to do some research onservice life of this device.In this paper, we analyze the failure of the sealing surface through two aspects. Oneis from the valve itself, and the other is based on the analysis of inner fluid. We introducesome basic theories of fatigue and necessary analyzing method concerning it first,selecting out the method to be used. To analyze the fatigue life of valve, we use ANSYSfinite element analysis software and MSC.Fatigue. at the same time. Initially, we analyzethe stress and strain of the valve actual condition by ANSYS. Through this, we know thecause of damage which satisfies the static strength is due to the fluctuation of temperature.Next, we calculate out the fatigue life of the valve sealing surface in key part, using thestrain caused by the fluctuation of temperature as the input which is obtained before byANSYS. We also study the relationship among fatigue life and the load, surface roughnessand surface heat treatment. Believe that the valve with heat treatment and surfaceprocessing good will prolong the service life of the valve.From the view of flow field, the internal flow field of steam drum platoon valve isturbulent motion. In this paper, we find out failure mechanism of the valve is caused bythe erosion of unpurified particles through the simulation of Fluent and some comparisonbetween the internal structure. The suggestion for improving the structure of the valvebase was presented. We studied the effect of degree of opening on the erosion on thesurface of valve. And we think it is better to avoid the medium opening.