A hollow exponential ultrasonic horn for aluminum melt degassing under power ultrasound and rotating flow field

Abstract

To meet the need of aluminum melt degassing, a hollow exponential ultrasonic horn was proposed. The numerical analysis showed that the amplification factor and shape factor of the horn will increase with the increasing central hole diameter. When the hole diameter is less than 20 mm, they increase slowly while rapidly once the hole diameter excessed 35 mm. The modal analysis and experiments indicated that the resonance frequencies of all the horns are very close to the set frequency, and the errors are less than 3%. Although the displacement amplitude differences are both more than 20 µm, the central hole horn is larger, which is consistent with the result of modal analysis. A simple aluminum melt degassing system employing the proposed hollow horn and rotary impeller was used to experiment on ZL101A aluminum melt, and the results indicated the more satisfactory degassing efficiency can be got by using the appropriate parameters.