Numerical Research Of Radial Force On Match Characteristic Between Guide Vane Position And Circular Casing In Reactor Coolant Pump

Nuclear main pump is the most important high-speed rotating equipment in pressurized water reactor(PWR)and must be able to withstand high temperature,high pressure,strong radiation corrosion and other environments for a long time.And it is precisely for the strict requirements,the safety and stability of the operation of the main pump are particularly important.However,the radial force of the main pump impeller often leads to fatigue damage of the pump shaft,which in turn affects the efficiency and longevity of the nuclear main pump.So it is important to explore the influence of the positional relationship between Guide Vane Position and Circular Casing on the radial force of the impeller.The flow passage components of nuclear main pump are mainly composed of three parts: impeller,guide vane and annular casing.And the match between the guide vane and the impeller determines the performance of the nuclear main pump and whether the nuclear main pump can be safe and stable operation.By changing the axial and circumferential position of the guide vane,the variation law of the impeller on the radial force is studied.In this paper,the design of a certain type of nuclear main pump model by myself was regard as the research object.The influence of the position of the guide vane on the radial force of the impeller is studied.Numerical simulation is used to simulate the whole flow field inside the core pump.The main research content and the results are divided into the following four parts:1.The effect of the axial position of five different guide vanes on the performance of the reactor coolant pump and the influence of impeller outlet pressure pulsation are analyzed by using the Fluent software to simulate the internal of the model reactor coolant pump.The results show that with the axial position of the pump guide vane under design condition,the maximum rate of change of head is 4.1% and the maximum rate of change is 4.0%.When the centerline of the pump casing exit pipe coincides with the guide vane outlet centerline,the efficiency and head of the pump are the highest in five design schemes.Which means that the optimal axial position of the guide vane can make the performance of the core pump to be relatively optimal.From the unsteady state,it is analyzed that the axial position of the guide vane on the impeller outlet pressure pulsation.The results show that it is possible to reduce the pressure fluctuation amplitude of the impeller outlet,improve the internal flow of the core pump and reduce the vibration inside the pump by reducing the axial distance between the outlet centerline of the pump casing and the outlet centerline.Which is beneficial to the safe and reliable operation of the nuclear main pump.2.The influence of axial position of guide vane on radial force of impeller of model main pump is analyzed.The results show that the axial position of the guide vanes will not only affect the pulsation amplitude of the impeller radial force,but also will affect the waveform changes.As the axial distance between the guide vane exit center line and the center line of the pump outlet pipe increases,the radial force of the impeller increases gradually as the impeller rotates one week,and the radial force gradually diverges.When the centerline of the model nuclear main pump casing exit coincides with the guide vane outlet centerline,the impeller radial force vector distribution is relatively more concentrated.And the impeller radial force of the most and average value also reached a relatively minimum.3.The influence of circumferential position of guide vane on radial force of model nuclear main pump impeller is analyzed.The influence of the circumferential position of the guide vanes on the radial force and performance of the main pump impeller are studied under design conditions.The results show that the frequency of the radial force pulsation on the impeller is dominated by the frequency of the blade passing,and periodical fluctuation with time.When the guide vane of the nuclear main pump is in a certain position,the distribution of the radial force vector of the impeller is relatively more concentrated,and the range of the numerical fluctuation is smaller.When the guide vane is in the best circumferential position,the radial force acting on the impeller on the average value decreased first and then increased as the flow rate changes.And in the non-design conditions,the radial force vector distribution acting on the impeller is relatively discrete.So in the design conditions can be a good way to improve the impeller radial force vector distribution,while reducing the pump vibration and noise.4.The influence of the matching between the radial guide vane and the annular chamber pump on the internal flow field of the nuclear main pump is compared and analyzed.The results show that,regardless of how the radial guide vanes are arranged,the vector distribution of the radial force of the impeller is closely related to the outlet pressure distribution of the impeller.And the flow from the inside of the annular pressurized water chamber can predict the radial force vector distribution of the impeller,but also from the guide vane to produce turbulent kinetic energy of the regional area size to predict the impeller radial force vector distribution.So as to avoid the long-term by the shaft due to non-uniform radial force,leading to its fracture and so on.It is hoped that this paper will provide some guidance for the researchers of the radial force of nuclear main pump and lay a solid foundation for the further theoretical design of nuclear main pump.