A PIV Study of The Cooling Air Flow in An Electric Generator Model

Report, 2012

One factor that affects the performance of a hydro power generator is temperature. The efficiency, the electric resistance, the cables, the windings, etc, are temperature-dependent. These make controlling temperature rise in a generator of high importance in order to minimize hot spots and material failure. In order to tackle the problem air is used as a cooling fluid, which circulates through the stator and rotor in the generator. A generator model has been specially designed to perform fluid flow measurement. 2D-2C PIV (Two Dimension - Two Component Particle Image Velocimetry) was used to measure the fluid velocity inside the stator channels. Stereo PIV (2D-3C) was used to measure fluid velocity outside of the stator body. The results show that the tangential velocity component dominates the flow outside the stator. Inside the stator channels the fluid moves radially with a large recirculation region (almost half of the channel width) behind the coil. The flow structure inside the channels is shown to be independent of the rotor pole position.