The New Research On Erosion Resistance Blowdown Valve Of MNPP Steam Generator

Compared with the Civil Nuclear Power Plant (CNPP), the Marine Nuclear Power Plant(MNPP) is very different from that in structure due to its special work environment andperformance requirement. The steam generator is primary loop and secondary loop workingmedium energy transfer equipment. Medium water in the U-shaped tube of primary loopquality requirements are very strict,there is almost no dirt, even so, for steam generator it stillhave strong corrosive. While the water of secondary loop for consumption greatly, can’t get agood quality control. Therefore, every certain period the steam generator can generate part ofthe dirt,and if not discharged it in time, it will cause the corrosion of the steam generator,effect the heat exchange and flow rate. Therefore, discharge the dirt through blowdown pipeeveryday is needed. Blowdown valve is an important valve that is connected on theblowdown pipeline control pipe opening and closing. And now in used blowdown valve hasmany problems, such as, sealing surface erosion, crushed, solid particles residue, and so on.In the paper, the valve is designed to solve the problems mentioned above. It isdistinguished with the traditional blowdown valve for the double sealing surface structure cangreatly reduce the erosion of the valve. On the basis of the previous research, the structure ofthe primary valve is to be improved aiming to deal with the eroding of the sealing surface,crushed, solid particles residue. By adoption of Pro/E, establish the flow field of the improvedblowdown valve model; mesh is generated by ICEM of ANSYS, and the blowdown valveopen process is numerically simulated by FLUENT software. Thus, obtain the pressurechange contours of the open process, velocity change contours, based on these parameters,the working state of the valve can be determined as well as the existing problem can be foundand solved. Finally, verify the theoretically analyzed results by experiments, contrast thetheoretical value with the actual value,then analysis of the reasons.In this paper we use two softwares Pro/E and ANSYS, modeling and calculation theinternal flow field of the improved blowdown valve, and then contrast analysis withexperiment results. It’s not only speed up the design phase but also save expenses. All in all, itis very significant in the design and manufacture of the blowdown valve.