Study On Three Dimensional Thermal And Flow Fields For A Canned Motor With Built-in Spiral Tube

With the growing of comprehensive strength and the increasing demand of electricity of our country,nuclear power generation plays an important role in power generation technology as a kind of efficient and clean energy.As an important part of nuclear power station,canned motor is the key equipment that affects the safety of power plant.How to achieve safe operation of canned motor and ensure its service life have always been the core concern of people.In this paper,the finite volume method was used to study the thermal and flow fields for a canned motor with a built-in spiral tube by a factory.Firstly,a simplified circumferential 1/4 three dimensional physical model of the canned motor with a built-in spiral tube was established and meshed.The SST k-ω was used in the simulation software,and the distribution characteristics of the thermal and flow fields of the canned motor under rated conditions were numerically simulated.The temperature distribution of stator strands,stator core,rotor bars and rotor core were analyzed in detail,the maximum temperature was determined to be 169.9℃ and the canned motor was in thermal safety state.Thermal and flow fields of cooling water was analyzed in detail and the maximum water velocity was determined to be 58.1m/s.Secondly,on the basis of constant physical model,the thermophysical parameters of cooling water,the heat transfer coefficient of casing surface and the gravity field were changed successively,and numerical simulation were carried out successively.The influence of thermophysical parameters of cooling water,the heat transfer coefficient of casing surface and the gravity field on the temperature field of canned motor was analyzed.The results show that the temperature field of the canned motor was affected by the thermophysical parameters of the cooling water and the heat transfer coefficient of casing surface,but the gravity field has no effect on the temperature field of the canned motor.Finally,the structure of the double-layer spiral tube heat exchanger was changed.The staggered double-layer spiral tube heat exchanger was changed to a parallel double-layer spiral tube heat exchanger,and the canned motor with parallel doublelayer spiral tube was simulated numerically.The temperature field of canned motor under two different arrangement modes was compared,and the heat transfer of cooling water under different arrangement modes was analyzed.The results show that the overall temperature of the canned motor with staggered double-layer spiral tube was higher than that the canned motor with parallel double-layer spiral tube,but the heat transfer of the cooling water with staggered double-layer spiral tube was higher than that with parallel double-layer spiral tube.In this paper,the numerical simulation of the thermal and flow fields of the canned motor with a built-in spiral tube was realized,and the temperature distribution law of the canned motor was obtained.It provides a basis for subsequent thermal stress calculation,and has reference and guiding significance for the design and development of canned motor.