Acoustic design principles for energy efficient excitation of a high intensity cavitation zone

23rd International Congress on Acoustics,integrating 4th EAA Euroregio 2019

Document identifier: oai:DiVA.org:ltu-76063
Access full text here:10.18154/RWTH-CONV-239450
Keyword: Engineering and Technology, Structural acoustics, Electronic systems, Engineering Acoustics, Teknisk akustik, Cavitation, Hydrodynamics, Ultrasound, Annan elektroteknik och elektronik, Mechanical Engineering, Elektroteknik och elektronik, Other Electrical Engineering, Electronic Engineering, Information Engineering, Electrical Engineering, Electronic Engineering, Information Engineering, Strömningsmekanik och akustik, Maskinteknik, Teknik och teknologier, Fluid Mechanics and Acoustics, Elektroniksystem
Publication year: 2019
Relevant Sustainable Development Goals (SDGs):
SDG 9 Industry, innovation and infrastructure
The SDG label(s) above have been assigned by OSDG.ai

Abstract:

Energy-efficient process intensification is a key aspect for a sustainable industrial production. To improve energy conversion efficiency high intensity cavitation is a promising method, especially in cases where the material to be treated is valuable and on the micro meter scale. Transient collapsing cavitation bubbles gives powerful effects on objects immersed in fluids, like cellulose fibers, mineral particles, enzymes, etc. The cavitation process needs optimization and control, since optimal conditions is multivariate challenge. This study focuses on different design principles to achieve high intensity cavitation in a specific volume in a continuous flow. This study explores some potential design principles to obtain energy efficient process intensification. The objective is to tune several different resonance phenomena to create a powerful excitation of a flowing suspension (two-phase flow and cavitation bubbles). The reactor is excited by sonotrodes, connected to two coupled resonant tube structures, at the critical frequency. Finally cavitation bubbles are initiated by a flow through a venturi nozzle. The acoustically optimised reactor geometry is modelled in Comsol Multiphysics®, and excited by dedicated ultrasound signals at three different frequencies. The effect of the high intensity cavitation is experimentally evaluated by calorimetric method, foil tests and degree of fibrillation on cellulose fibers.

Authors

Örjan Johansson

Luleå tekniska universitet; Drift, underhåll och akustik
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Taraka Pamidi

Luleå tekniska universitet; Drift, underhåll och akustik
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Vijay Shankar

Luleå tekniska universitet; Drift, underhåll och akustik
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Torbjörn Löfqvist

Luleå tekniska universitet; EISLAB
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