| The YJKK series motors are new products developed based on the YKKseries motors with medium-sized and high-voltage. The design purpose is toreduce the volume and increase power density. Compared with the original motor,the center high in new series is two levels’ lower on average in the case of thesame capacity. So the power density is increased. According to the geometrysimilarity law of the motor, along with the increasement of power density, theinternal heat dissipation problem is bound to become increasingly prominent. Ifthe temperature rise is too high, such phenomenon as discharge, short circuitwould appear. Therefore, it is necessary to improve the cooling system and analysis thefluid field and temperature field clearly and accurately to ensure motors operate safelyand reliably.In most cases, usually only the analysis model of certain parts of the regionis established and afterwards some estimates are carried out on the fluid flowcharacteristics of the overall model when the distribution of cooling gasparameters within high-voltage motors are calculated. In that case, the empiricalformula and test need to be fitted if boundary conditions are to be applied.Therefore, existed research results are not fully applicable for the motor withnew structure. In order to describe the fluid flow and pressure distribution of theinternal motor truthfully and accurately, this paper take a YJKK500-4,2500kWcompact motor with medium-sized and high-voltage as an example, establishedglobal fluid model based on the theory of fluid mechanism and heat transfer,combined with the size of the motor and the actual operations, analyzed the fluidand temperature distribution of the motor. On this basis, the cooler and fan shield structure was improved. Meanwhile, three kinds of optimization schemes wereput forward according to the original internal fan’s relatively small flow pressureand flow rate. Additionally, in terms of the complexity of the ventilation structure,a localized model was established combined with the appropriate boundaryconditions, thus, analyzed the fluid and temperature coupled field. The resultprovides the theoretical foundation for the research and improvement of theYJKK serious motor. |
