Research On The Hydraulic Design Of Canned Nuclear Coolant Pump With High Efficiency Low Axial Force And Low Hydraulic Pulsation

At present,the development of autonomous CAP 1400 canned coolant circulating pump is being carried out.New design of hydraulic parts and targeted research must be carried out.It requires the efficiency of CAP 1400 hydraulic component is higher than 85%;Second,the hydraulic axial force requirements is less than 230000N;Third,it is necessary to reduce the pressure fluctuation of hydraulic components;Hydraulic components impeller and diffuser design restrictions:structure and size limit of spherical case,the installation location restrictions,diffuser diameter restrictions,processing requirements of manufacturing hydraulic components.For the three key hydraulic performance efficiency,axial force and hydraulic pulsation,first established scale hydraulic model.Use numerical simulation and experimental verification to study the relationship between geometric and hydraulic performance.The influence of blade stacking,meridional flow passage and blade numbers on the efficiency and axial force is revealed.A new impeller and blade coordinated optimization method is established.And an axial force correction formula considering the influence of impeller outlet geometric parameter is established.The design criteria of high efficiency and low axial force impeller under restricted conditions are put forward.And the design of high efficiency and low axial force of hydraulic components of nuclear main pump is realized.On the basis of high efficiency and low axial force,a kind of unsymmetrical axial channel staggered blade was designed and studied.The pressure fluctuation and unsteady radial force were studied under staggered blade.Further,the low pulsation design of the hydraulic components of the nuclear main pump is realized.Finally,the design,manufacture and relevant test verification of the model pump are completed.Research shows that:the positive inclined stacking of impeller blade is helpful to improve the efficiency;impeller blade number meeting different processing requirements to enhance efficiency is 5.Diffuser and impeller outlet width ratio should be increased,and diffuser and impeller outlet diameter ratio should be increased too.Half horn diffuser design helps to improve the efficiency under the installation limit.The impeller outlet diameter ratio has effect on axial force,reduce the diameter ratio in favor of reducing the axial force.The axial force correction formula using diameter ratio is consistent with CFD calculation.Under high efficiency and low axial force,the geometric parameters of the impeller outlet should be calculated according to the method of increasing the specific speed.The impeller inlet diameter has a reasonable value in consideration of both efficiency and axial force.The influence on the pressure fluctuation is weaker.Staggered blade impeller can significantly reduce the pressure pulsation,the staggered blade diffuser can effectively reduce the radial force.The same angle and the same flow rate staggered is the best for both impeller and diffuser.Through the study,low axial force impeller and diffuser are given.Hydraulic components designed by multiple constraints studies,and the design efficiency of hydraulic components is 84.9%.The estimated prototype efficiency is higher than 88%,the axial force is 190000N.The efficiency and axial force meet the design requirements.The hydraulic scheme has been as one of the hydraulic components of the CAP 1400 nuclear pump.