| The canned nuclear coolant pump is widely used for small nuclear power plant such as warships and some third-generation advanced pressurized-water reactor.Cooling circulation system of small nuclear power plant bring a lot of hydraulic losses in the operation process because of can,the bidirectional serpentine cooling circulation pipe,auxiliary impeller and other components.And the auxiliary impeller which provides the fluid power for the cooling circulation system not only has a great influence on the starting performance of the unit,but also makes the flow and thermal equilibrium of the cooling circulation system more complicated.Under the premise of ensuring cooling and lubrication performance requirements,how to effectively reduce the internal loss of cooling circulation system,realize the stable starting of the unit and ensure efficient and safe operation is an urgent problem to be solved.Therefore,according to the structural characteristics and special operating conditions of the canned nuclear coolant pump for small nuclear power plant,how to accurately master and control the hydrodynamic characteristics of its cooling circulation system is one of the key technologies in the process of development.This paper researched a cooling circulation system of a nuclear power plant for warships.To explore a way to accurately calculate internal water friction loss,analyze the composition and influencing factors of internal water friction loss,master the distribution law of water friction loss in the system and research the influence of internal structure of the cooling circulation system for guiding the design optimization of cooling circulation system.The main research contents and conclusions are as follows.(1)According to the structural design characteristics of the main components of the cooling circulation system for nuclear canned motor pump,the clearance of can,designed preliminarily auxiliary impeller,cooling circulating pipe and bearing.Based on the numerical simulation method,calculated the hydrodynamic characteristics of the cooling circulation system at 10 ~ 3000r/min.And analyze the sources and causes of internal water friction loss in detail.The key factors affecting the performance of cooling cycle system are the auxiliary impeller and can.At the same time,according to the numerical heat transfer method,the heat balance problem caused by large loss in the cooling circulation system is verified.The results show that the bidirectional serpentine cooling circulation pipe can satisfy the cooling demand of the cooling circulation system.(2)According to the numerical calculation results of water friction loss,based on Newton’s law of internal friction and plate turbulent boundary layer theory,the water friction loss of the rotor can under laminar flow condition and turbulent flow condition is calculated theoretically.The results show that the water friction loss of the rotor can calculated theoretically is very close to the results of numerical calculation.It can be used forapproximate calculation of water friction loss similar to Taylor couette flow,which provides reference for preliminary design of cooling cycle system.(3)Aiming at the auxiliary impeller and can which affect the cooling cycle performance of the system,studied and analyzed the hydrodynamic characteristics of the gap runner and the auxiliary impeller by using the performance prediction method based on computational fluid dynamics by changing the gap of can and the number of holes of the auxiliary impeller.The results show that the water friction loss can be reduced by increasing the gap of can.The performance of the cooling circulation system can be improved by reducing the outlet angle of auxiliary impeller and increasing the number of holes. |
PDF Full Text Request