Configuration Analysis And Numerical Simulation Of Ultra-supercritical Bypass Valve

Along with the increase of electricity requirement,coal-fired power whichundertake the burden of peak-regulation is developing rapidly,and the requirement ofpower station valves are also rapid development.Therefore,the document[2010]335isissued by National Energy Commissom, Ministry of the Science and Technology《National Energy Administration prints and distributee the notice thatultra-supercritical thermal power generating units’key value localization》,and putforward to the high-end power station valves.As indispensable unite to generatingsets,bypass valves are the most important equipment in terms of adjusting andcontrolling steam.In high pressure of the steam tubine bypass systems.Bypass valvesplay the important role in starting and loading steam turbine,which also guarantee thewhole unite running smoothly and improve the unit of security and flexibility throughthe closely linked to other equipments.In the ultra supercritical unites bypasssystems,bypass valves endure rigorious condition.In such conditions the importpressure is30MPa and the temperature is600℃,safety work is more important.Taking the hoops connection structure as an example, the dangerous sectionstructure model of the hoops are established,and the stress formula and the stressjudgement basis of the hoops are get.By the softsare of ANSYS,the hoop parameterizedmodeling is established,and the stress distribution rules and the maximum equivalentstress in the most dangerous section of the hoops are get.By the design Explorermodule of ANSYS,the hoops are optimized,and the graphs are get which keyparameters affect von-mises stress.Find out the best size of each key parameters byanalyzing each key parameters on the stress value of the size of the influencedegree.Keep the maximum von-mises in permited range and make the stressdistribution more reasonable in order to improve the hoop in the stability and securityperformance.By the plastoelasticity,the thermal stress are analysied in bypass valves’ cylindricalbody and spherical body.The formulas are derived to calculate thermal stress,andaccording to which, the curves are come out.By the softsare of ANSYS, bypass valves’temperature field is analysied,and the different temperature between interior wall andexterior walls.Use temperature filed analysis distribution rule of thermal stress and multiple stress and judge each part of stress.According to the internal structure and the flow field characteristics of the bypassvalves,the multi-stage throttle holes are adopted to throttle step-down in bypassvalves.Based on the structure of the small holes multistage throttling,the bypassvalves’internal flow field of the two-dimensional calculation model is established,numerically simulates the2d port flow field by FLUENT.By two models-time-averaged flow field and large eddy model,the flow field of the pressure,velocity,and eddy current strong distribution law are obtained under the unsteadyturbulent.According to analyse the pressure,velocity,and eddy current strong changerules,study that noise and vibration might also be influenced by pressure, velocity, andeddy current strong,and have a preliminary understanding of the reason of bypassvalves’ vibration and noise.