Analysis Of Hydrodynamic Performance Of The Sodium Pump In The Second Circuit Of Fast Reactor And Effect Of Guide Vane Parameters On Its Performance

Sodium-cooled fast neutron reactor system is one of the fourth generation nuclear energy systems,and the sodium pump in its second circuit is the core equipment of the whole system.Based on the viewpoint of efficiency and safety,in order to explore the effect of the key parameters of guide vane on the hydrodynamic performance,pressure fluctuation and radial force of the sodium pump in the second circuit of fast reactor,the single stage single suction centrifugal pump with a specific speed of 95was taken as the research object,and the exterior characteristics parameters,internal flow field,pressure fluctuation and radial force characteristics of the model pump under different flow rate,different guide vane inlet diameter and different guide vane number were analyzed by combining theoretical analysis and numerical calculation.The specific contents of this paper are as follows:1.The effect of flow rate on the performance of the model pump.Through steady calculation,the hydraulic performance parameters and internal flow field of the model pump under different flow rates are analyzed.In the range of0.3-1.3Q_opt,the calculated values of head and efficiency of sodium pump are in good agreement with the experimental values,and the changing trends of both are basically the same.Among them,the efficiency value of sodium pump increases first and then decreases with the increase of flow rate,and there is a high efficiency area in the range of 1.0-1.1Q_opt.The internal flow condition of sodium pump is good at design operating point and large flow condition.Under the condition of small flow rate,the internal flow state of sodium pump is poor.Through unsteady calculation,the pressure fluctuation,the radial force fluctuation of the rotor and its distribution at each measuring point in the model pump under different flow rates are analyzed.The main frequency of pressure fluctuation at each measuring point of sodium pump under different flow rates is blade frequency,and the frequency domain distribution of pressure fluctuation at the outlet of guide vane is affected by complex eddy structure.In the vicinity of the design flow condition,the pressure fluctuation amplitude of each measuring point is very similar to the spectrum characteristics;in the case of small flow rate deviating from the design flow condition seriously,the pressure fluctuation amplitude of each measuring point increases.At the same time,the main frequency of the radial force pulsation on the rotor decreases,the intensity of the pulsation increases obviously,the distribution of the radial force vector is irregular,and the spectrum characteristics and vector distribution of the radial force pulsation on the rotor are closely related to the flow field structure.2.The influence of guide vane inlet diameter on the performance of the secondary circuit coolant pump for sodium-cooled fast reactor.Five kinds of model pumps with different guide vane inlet diameters were taken as the research object.Through steady calculation,their hydraulic performance and internal flow field were compared and analyzed.The hydraulic performance of the model pump with guide vane inlet diameter of 568mm is the best at the design operating point and its vicinity.At the design operating point,when the guide vane inlet diameter is 560mm,the hydraulic loss of the dynamic at static cascade clearance of the sodium pump is the smallest;and when the guide vane inlet diameter is 576mm,the hydraulic loss of the guide vane passage is the smallest.Through unsteady calculation,the pressure fluctuation,radial force fluctuation and distribution characteristics of the model pump under different guide vane inlet diameters are analyzed.The pressure fluctuation of each measuring point is mainly affected by static and dynamic interference.With the increase of the guide vane inlet diameter,the fluctuation amplitude of each measuring point decreases gradually,and reaches the minimum when the guide vane inlet base circle diameter is 576mm.With the increase of cascade clearance,the pressure fluctuation amplitude at the inlet,middle and outlet of guide vane decreases gradually,and the model pump with relative clearance of 9.09%has the lowest fluctuation amplitude.In addition,the radial force fluctuation of impeller is also affected by static and dynamic interference.With the increase of cascade clearance,the main excitation frequency of radial force pulsation decreases gradually,and the high frequency pulsation weakens gradually.When S=4.55%,the main frequency amplitude of the radial force of the rotor is the largest,and the radial force vector of the rotor varies most obviously with its rotation.When S=3.03%,the main frequency amplitude of the radial force of the rotor is the smallest,the distribution of the radial force vector of the rotor is the most concentrated,and the balance effect is the best.3.The influence of guide vane number on the performance of the secondary circuit coolant pump for sodium-cooled fast reactor.Taking four model pumps with guide vanes of 8,9,10 and 11 as research objects,their hydraulic performance and internal flow field state were compared and analyzed by steady calculation.Under 0.8-1.2Q_optpt conditions,the model pump with 9 guide vanes has the best external characteristics.Under the standard operating conditions,the guide vane channel of the model pump with 9 guide vanes has the best diversion effect,and the flow condition in the pressurized water chamber is also good,and the energy loss in both places is low.Through unsteady calculation,the pressure fluctuation,radial force fluctuation and distribution characteristics of the model pump under different guide vane inlet diameters are analyzed.The pressure fluctuation at each measuring point and the radial force fluctuation of the rotor are affected by the static and dynamic interference under different number of guide vanes.With the increase of guide vane number,the pressure fluctuation amplitude at the inlet,middle and outlet of guide vane decreases first and then increases.When the number of guide vanes is 10,the pressure fluctuation amplitude of each measuring point is the lowest.When the number of guide vanes is 11,the radial force acting on the rotor changes most obviously with time;when the number of guide vanes is 8,the balance effect of the radial force acting on the rotor is the best.