R&D On An Analytical Code For Flow Induced Vibration Of Heat Exchange Tube In Steam Generator Of Fast Reactor

In the fourth generation of nuclear power technology,as the fastest progress in research and development,the sodium-cooled fast reactor is highly focused by Chinese government because it is the closest to meet the needs of commercial nuclear power plant reactor type.China has completed the construction of experimental fast reactor,and plans to build large-scale fast reactor demonstration power station in Fujian Province,which is designing.In the design,the steam generator is one of the key equipment of the whole power plant.The heat exchange tube inside it not only has the task of transferring the heat of the nuclear island to the conventional island,but also the boundary between the nuclear island and the conventional island.The internal flow of heat exchange tube is vapor with high pressure and high temperature,the outer flow is liquid metal sodium with high temperature.Flow induced vibration will occur when they flow past heat exchange tube.If the tube wall of the heat exchanger tube damaged by flow-induced vibration,liquid sodium and water vapor may occur chemical reaction,which may affect the safe operation of fast reactor nuclear power plant.Therefore,engineers should give sufficient attention on the heat exchanger tube-induced vibration problems in the design stage.In this paper,the flow-induced vibration analysis theory of the conventional tube-and-tube heat exchanger tubes is investigated and summarized as a complete set of flow-induced vibration analysis methods.In the analysis of flow-induced vibration of tube-shell heat exchangers,it is necessary to analyze the modal characteristics of tubes,the mechanism of induced vibration and the degree of wear.The modal characteristics of heat exchange tubes include natural frequency and damping,the natural frequency has a fairly mature theory,and the damping can only be calculated using semi-empirical formula,and the accuracy is not high enough;flow induced vibration mechanism is divided into cross flow and axial flow.For cross flow,it has some accepted mechanism: vortex shedding,turbulence excitation,fluid elastic instability,acoustic resonance.In these trigger mechanism,the acoustic resonance will occur when the shell side fluid is gas.In this paper,the shell side fluid of the object of study is liquid,so the acoustic resonance will not be discussed.For axial flow,it has no boundary layer separation,so vortex shedding won't produce and the parameter resonance will instead.The results of calculation of the parameters such as natural frequency,amplitude of heat exchange tube will be used to determine the flow induced vibration of heat exchange tube.After that,Achard wear equation will be used to evaluate the service life of heat exchange tube.After finishing the theoretical summary,the accuracy of the natural frequency calculation method is verified by experiment and numerical calculation,and the rule of the nonlinear restraint strength between the heat transfer tube and the thickness of the support plate is obtained.After that,this paper selected and optimized the basic theory of the flow-induced vibration analysis appropriately,formed a flow-induced vibration analysis theory for heat exchanger tubes of fast reactor steam generators.Based on that,this paper exploited a specialized program for steam generators of fast reactor by using Fortran.