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