Analyzing regularity of interpolar air motion and heat dissipation coefficient distribution of a salient pole synchronous generator considering rotary airflow

Abstract

The extreme attention should be paid to cooling performance of air-cooled synchronous generators in order to ensure that the temperature rise of each part is within the allowable range. It is necessary to know losses distribution, cooling airflow rate distribution laws, heat dissipation coefficient distribution and temperature distribution characteristics. Considering the influence of rotary airflow and yoke ventilation duct structure on air motion, the physical parameters and the motion characteristics of interpolar air were analyzed in three cases. These cases were considered respectively when the rotor was in a rotating or non- rotating state and the yoke ventilation ducts were intake air, and when the rotor was in a rotating state and the yoke ventilation ducts were not intake air. Based on Multi-Reference Frame, the finite volume method was used to solve the fluid-solid coupling numerical simulation of the solving domain. Taking a 250 MW air-cooled hydro-generator as an example, the air velocity of each air cooler was measured and the inlet air velocity of the rotor support was calculated. By calculating the average temperature of the excitation winding in the steady state, the measured value and the simulation result were compared, and the correctness of the calculation method was verified.