Calculation and analysis of complex fluid flow and thermal fields in a fully air-cooled hydrogenerator

Fully air-cooled hydrogenerators are applied widely in power stations because of advantages such as high efficiency, simple structure, and easy maintenance. This study investigated fully air-cooled hydrogenerators, and a three-dimensional fluid and thermal coupling analysis model of a hydrogenerator was proposed. Using the finite volume method, the changes in complex fluid velocity in the stator and rotor zones at different times were determined. Additionally, temperature changes in metal parts and insulation in the hydrogenerator were investigated with respect to time from the start to steady state operation of a hydrogenerator. In the study, the time required for the temperatures of different hydrogenerator parts to reach a steady state was predicted. Following the starting of the hydrogenerator, the temperature distribution of different parts at the same time and the changes in the temperature distribution of parts at different times were determined in the hydrogenerator. The surface heat-transfer coefficient distribution law on the surfaces of rotor exciting winding was studied. The calculated temperature result was compared with the measured value, and the results indicated that the calculated value of temperature agreed well with the measured value. Thus, the study indicated the feasibility of designing a fully air-cooled hydrogenerator from a thermal analysis viewpoint.