Study On The Ventilation And Cooling Of Brushless Exciter

For the exciter,researches often focused on the electromagnetic design,structural design,the rectifier circuit design and optimization at home and abroad,but lacked on the exciter ventilation and cooling,particularly with respect to the researches on three-dimensional flow and temperature field numerical simulation aspects of stator,rotor and rotary rectifier plate were rarely reported.Therefore,this study has important scientific significance.In this paper,a prototype of some type Siemens brushless exciter which is introduced by a company from Japan was estabilished as a model to conduct independent research and development design for west-east gas 20MW high-speed non salient pole synchronous motor.Ventilation and cooling of the exciter is the main research direction to ensure that the internal components do not overtemperature,especially for the rotating rectifier diodes and rotor winding bars.The finite volume method(FVM)was adopted,the FLUENT software was used to analyze and simulated study a single rotating fluid factors and two design schemes,distribution characteristics of flow and temperature fields with corresponding cases were obtained.First,in view of the two rotating device in the exciter,the flow field characteristics mechanism when a single rotating member is roating and sucting was analyzed and the feater of flow field distribution was got.Then,in allusion to the brushless exciter sheme 1,internal three-dimensional flow field and temperature field numerical simulation were calculated,the integrated flow and temperature field characteristics caused by coaxial two rotating parts rotating at the same time were inversed.Based on these studies,changing the entrance and exit position,researched the features of internal three-dimensional flow and temperature field of brushless exciter scheme 2,analyzed the mechanism and exploring to study the interaction of two rotating flow field,the interaction between the flow field and temperature field.The mass flow rate of the exit and temperature close to base near the shaft under the actual running were measured.Compared with the experimental results and the simulation results,the numerical simulation process of the simplified physical model selection,the setting of boundary conditions and the accuracy of the calculation results are verified.It provides a theoretical basis for the future development of ventilation and cooling design for brushless exciter using by synchronous motor.