engleski

SOURCES OF WINDAGE POWER LOSS IN SALIENT POLES HYDROGENERATOR

Due to the fact that hydro-generators are primarily electrical machines, traditionally insufficient attention is paid to aerodynamics within the machine. Consequently, the existing analytical methods for windage loss calculations, which in the hydro-generator can participate with more than 30% of total losses, are quite simplified and are based largely on empirical data for each specific design. This paper presents the results of stationary, 3D numerical calculations of salient-poles hydro-generator windage loss, carried out with commercial CFD tool. The model was validated against relevant published experimental results for protruded rotor-stator cavities, and then similar approach was used to simulate air flow through model of hydro-generator. Calculation results of hydro-generator model were compared with the results of the on-site calorimetry measurements. The simulations were performed with k-ω SST turbulence model and the rotor motion is modeled by “multiple reference frame” approach. Validation of CFD model on protruded rotor-stator model showed good agreement with measurements: departure of calculated windage loss are lower than 8.5% of the measured. Comparison of the calculated results with the on-site calorimetry measurements showed greater departure: 14.8%. Numerical calculations enabled insight into the windage loss contribution of each main structural element: salient poles, axial fan and various protrusions and reinforcements. Conducted calculations represent contribution to understanding of the origin of windage loss in salient poles hydro-generators. Further research is needed to clarify and reveal the details of complex interactions between different construction elements and their influence on windage loss of salient-poles hydro-generators.

CFD ; hydro-generator ; salient poles ; windage power loss

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