Layout of spillway aerator air ventsand its effect on air supply

Sammanfattning: Chute aerators are constructed to protect spillways from cavitation damage.They function by launching the water ow as a jet and supplying airunderneath since having air entrained into the water is an eective way tomitigate cavitation. This report looks at Bergeforsen, a dam in northernSweden, and its spillway as a basis for investigating how altering the aerator'soutlet alters its performance. Five dierent designs are tested using CFD with ANSYS Fluent 17. The designs are evaluated with regard to totalair ow, air ow distribution, duct pressure distribution, cavity length, andair concentration in water jet.It was found that designs with more even duct pressure distribution, thattransported air further toward the spillway center, had somewhat reducedtotal air supply compared to designs that released more of its air in theearly part of the duct. Consequently there appear to be a trade o betweeneectively distributing the air and providing more air ow. The currentdesign used by Bergeforsen strikes this balance quite well, better than theother tested designs.