Analysis of 3D Stator Thermal Field base on Coupled Fluid Field Calculation of Stator and Rotor for Hydro-generator

摘要

The rotor of hydro-generator is something like a cyclone and the fluid field produced by high speed rotation is very complex. The numerical method is applied in this paper to compute the fluid field generated by the rotation of rotor and the distribution of fluid field is obtained. The continuity equation to describe flowage of coercible air is presented as analysis model and the corresponding Navier-Stokes equations and equation of conservation of momentum is given. Based on the Numerical Heat Transfer (NHT) theories, the cooling system of stator is analyzed by establishing the 3D mathematical model of heat transfer of stator and fluid in the radial ventilation groove. Calculation of the fluid field and thermal field is performed by finite volume method. For a 320MW hydro-generator, the velocity distribution and fluid field distribution is calculated and the results are discussed in details, subsequently, the influence of fluid distribution on the thermal distribution is also analyzed. The results can provide theoretic supports for the cooling system calculation and the optimal design and safe operation of hydro-generator both will benefit from these analysis. Under the analysis of rotor fluid field, the velocity distribution of fluid in the radial groove is calculated and the calculated temperature results at rated load are compared with the tested values. The heat fluxes of the stator calculation region are analyzed, and the heat transfer process is explained unambiguous.