Flow And Strenth Analysis On Ultra Supercritical Double Reheat Steam Turbine Valve

Two intermediate reheat adopted in the conventional Rankine cycle.is the double reheat technology,this technique can effectively improve the efficiency of the whole thermal cycle.With the development of steam turbine technology,the new type of primary reheat unit has increased the inlet steam parameters to the limit that the high temperature material can bear.Therefore,in order to further improve unit efficiency and reduce coal consumption,the double reheat technology is an important way.After analysis,if the double reheat technology is applied to the million degree ultra supercritical unit,the thermal efficiency of the unit can be increased by 3.3% to 3.6% compared to the conventional reheat unit.According to the thermodynamic cycle analysis,the design of the steam turbine is faced with such problems as the increase of the main steam pressure,the increase of reheated steam temperature,and the addition of a high temperature reheat cylinder to the shaft system.Especially,the design of high temperature and high pressure parts on steam turbine has brought great challenges.The valve,as one of the key components of the steam turbine,needs to bear the highest inlet steam temperature and the inlet steam pressure.The working environment is in bad condition.In this paper,the high pressure valve of the double reheat unit is taken as the object of study.The flow characteristics,strength performance and fatigue life of the valve are calculated,analyzed and evaluated.First of all,by the software CFX as a platform to CFD flow calculation,the high pressure valve of double reheat unit would be analyzed.Through the different flow conditions of three-dimensional steam flow analysis,flow field characteristics and the loss of high pressure valves would be obtained.Then high pressure valves performance of double reheat unit would be analyzed.Secondly,based on the finite element software Abaqus,the high pressure valve of double reheat unit would be calculated and analyzed.According to the steady temperature field analysis,stress field analysis and high temperature creep strength analysis of valve body,the performance of the valve in the structure intensity would be achieved.Finally,by the research of structure stress of valve after hot or cold shock on the valve,the variable load?unit start and stop conditions affected the valve life analyzed.The life loss under different working conditions is obtained,which provides a basis for the on-site operation of the start-up and shutdown of the control unit.Through this study,can ensure that the high pressure valve of the double reheat unit was developed successfully.It lays a good foundation for the successful development of the double reheat unit.and provide reference for the analysis and research methods of the same type of high temperature parts.