Research On Performance Optimization Of Reactor Coolant Pump Based On Hydraulic Design Of Guide Vane

The development of nuclear power is currently an important energy strategy in my country.In order to improve the safety of nuclear island secondary circuit system operation,it is of great significance to carry out optimization research on hydraulic performance and vibration performance of reactor coolant pump.On the basis of optimizing the hydraulic structure of the guide vane,this paper aims to improve the overall hydraulic performance of the reactor coolant pump and reduce the flow-induced vibration.The whole computational domain is divided into a hexahedral structured grid,and the SST-DDES turbulence model is applied based on the value of unconstant constant Calculate and study the influence of the number of vanes,the inlet throat area and the diffusion of the guide vane on the hydraulic performance and vibration performance of the reactor coolant pump,in order to provide a theoretical reference for the hydraulic design process and optimization methods of the reactor coolant pump guide vane.Since the number of vanes of the guide vane is an important factor that affects the hydraulic performance and vibration performance of the reactor coolant pump,the relationship between the change of the number of guide vanes and the hydraulic performance and vibration performance of the reactor coolant pump is determined.Reasonable number of guide vanes when the overall performance is optimal.The results show that with the increase of flow,the influence of the number of guide vanes on the hydraulic performance of the reactor coolant pump gradually decreases.After reaching the design flow,the hydraulic performance is basically not affected by the change of the number of guide vanes;at the same time,the number of guide vanes is increased.The number of blades can reduce the vibration amplitude of the main frequency of the impeller outlet and the guide vane outlet,and is beneficial to improve the flow stability of the liquid flow in the pressurized water chamber.On the whole,when the number of vanes of the guide vane is 13,the overall performance of the hydraulic performance and vibration performance of the reactor coolant pump is better.After the number of vanes of the guide vane is determined,the reasonable flow area of the inlet throat of the guide vane channel is determined on this basis.The inlet throat area of the guide vane is one of the key geometric factors that determine the performance of the guide vane.It is different from the conventional hydraulic design method of the guide vane.The ratio between the absolute flow velocity of the impeller outlet and the absolute flow velocity is defined as the velocity ratio.The absolute velocity of the impeller outlet is integrated into the hydraulic design of the guide vane inlet geometric parameters through the concept of velocity ratio,and the influence of the change of the velocity ratio on the hydraulic performance of the reactor coolant pump is discussed.The impact of vibration performance,and determine the best value of the velocity ratio when the overall performance of the reactor coolant pump is optimal.The results show that:the change of velocity ratio has a relatively small impact on the power of the reactor coolant pump shaft,but it has a more obvious impact on the hydraulic loss and efficiency.When the velocity ratio is between 0.55and 0.60,the hydraulic loss in the pressurized water chamber is significantly reduced,and the efficiency Significantly improved;when the velocity ratio increases,the vibration amplitude of the main frequency of the pressure pulsation in the impeller and guide vanes gradually decreases,but the amplitude of the low-frequency vibration in the pressurized water chamber is not much different,and the amplitude of the high-frequency vibration increases with the velocity ratio.As the pressure pulsation in the pressurized water chamber is the direct excitation source that affects the vibration characteristics of the pipeline system,when the vibration characteristics of the pressurized water chamber are the main reference object,the velocity ratio is between0.50 and 0.55.The vibration performance of the system is relatively good.From the comprehensive comparison of the hydraulic performance and vibration performance of the reactor coolant pump,when the velocity ratio is 0.55,the overall performance of the reactor coolant pump is better.However,the velocity ratio obtained by the conventional hydraulic design method of the guide vane is 0.51,and the pump performance cannot be optimized.It can be seen that using the velocity ratio method and determining its optimal value can simplify the optimization process of the guide vane hydraulic design and effectively improve the performance of the guide vane and reactor coolant pump.After determining the specific values of the geometric parameters of the inlet throat of the guide vane,the overall hydraulic structure of the guide vane was optimized.Based on the concept of diffusivity,the influence of the change of diffusivity on the hydraulic performance and vibration performance of the reactor coolant pump is discussed by changing the exit area of the diffusion section and the length of the diffusion section through the strategy of superimposing the optimization one by one.The results show that the method of first determining the throat area of the guide vane outlet and then determining the length of the guide vane diffusion section,when the diffusion is 0.081,the hydraulic performance of the reactor coolant pump is better;the vibration amplitude of the main frequency in the impeller and the guide vane It increases with the increase of diffusivity,and the vibration amplitude in the pressurized water chamber generally decreases with the increase of diffusivity.From a comprehensive analysis,when the diffuser of the guide vane is 0.081,the hydraulic performance and vibration performance of the reactor coolant pump are relatively good.By comparing the performance of the optimized hydraulic design scheme of the reactor coolant pump with the original design scheme,it is found that the hydraulic efficiency of the optimized design scheme is significantly improved than the original scheme under high flow conditions,and the design operating point is increased by1.8%,It is increased by 2.9%at the 1.2Q_doperating point,and the vibration amplitude of the pressure is reduced to a certain extent.The research content of this paper provides methods and theoretical guidance for the hydraulic design of guide vanes.