Hydraulic Design Optimization And Strength Check Of Rotor For Molten Salt Pump At High Temperature

This manuscript,supported by the key project of Jiangsu province's development program(BE2015129)and key research development project of Zhenjiang(GY2016018),is to optimize the hydraulic geometric parameters of molten salt pump at high-temperature.Molten salt,duing to the advantages of no heat transfer,uniform heat transfer,low system pressure,safety and reliability,is an important cooling heat transfer medium.The molten salt pump with high-temperature molten salt is the "heart" of the fourth-generation nuclear reactor system,but there is less research on it at home and abroad.With the development of the domestic manufacturing industry,some domestic manufacturers have begun to do some localization research on molten salt pumps based on the original of foreign products,but most of the products are only used in chemical production.There are fewer researches on molten salt pumps in nuclear power,so the research and development of molten salt pump at high temperature has become an important issue in current research.The molten salt pump prototype(Q=20.2m3/h,H=9m,n=1450r/min)at high temperature is the research object in this manuscript,whose maximum working temperature is 500°C.The practical statistical analysis is carried out to do the work of the hydraulic geometric parameters of overcurrent components.Then,combining the numerical simulation and the experimental research to analyze the internal flow law of high-temperature molten salt pump and to find the change of the stress and the rotor.The main research contents are:1.Hydraulic design and orthogonal design are carried out with 8 geometric parameters such as impeller inlet diameter D0,impeller blade outlet width b2 and vane diffuser number Z,then 18 hydraulic geometric parameter models are obtained.Based on the simulated results of 18 sets of preliminary designed molten salt pump prototypes,three sets of hydraulic geometric parameters models were obtained through stepwise regression analysis,quadratic polynomial regression analysis and BP neural network model analysis.Then,detailed numerical simulations of the external characteristics of the above hydraulic models were performed,and finally a set of hydraulic geometric parameter combination models with the best performance were obtained.2.Based on the test and simulation results of the molten salt pump prototype,the flow law of the high-temperature molten salt pump was analyzed.The test results prove that the pump performance meets the design requirements.It is found that the static pressure in the impeller flow channel is significantly reduced from 300°C to 400°C at the same flow rate,and the static pressure change trend in the impeller flow channel is not obvious from 400°C to 500°C through numerical simulation.When the operating temperature of the molten salt pump is 500°C,some vortexes appear inside the impeller and the vane diffuser at the point where the flow conditions are designed,and the flow of the fluid in the vane diffuser is turbulent.3.For the change rule of the pressure pulsation in the molten salt pump at 500°C,it is found that the pressure pulsation at the inlet pipe and outlet pipe has no obvious regularity,and the monitoring points in the outlet pipe have high frequency pressure pulsation under the small flow rate condition.The main frequency variation rule of the pressure pulsation in the impeller is related to the number of vane diffuser,and the pressure pulsation wave decays faster in the vane diffuser than that of the impeller.4.The fluid-structure coupling analysis of high temperature molten salt pump shows that when the flow field conditions are the same,the deformation degree between the blade under the coupling of fluid-structure heat and heat-structure interaction was not big.The maximum deformation of fluid-structure coupling blades is about 40 times compared to that of the fluid-structure coupling.Through the thermo-mechanical coupling,it was found that the maximum deformation position of the pressure side of the blade occurs at the outer edge of the impeller.When the fluid-structure coupling action occurs,the strain law of the blade is similar to the strain law of thermo-mechanical coupling.The position where the maximum equivalent stress of the impeller is mainly concentrated on the area where the blade meets the front and rear cover plates at the outlet of the impeller.There is a different degree in stress concentration in the area where the blade contacts the impeller hub.5.Through the strength analysis of the molten salt pump prototype rotor,the results show that the prototype rotor components meet the 500°C operating strength requirements well.