Numerical Investigation of Rectified Diffusion for an Acoustically Induced CO₂ Gas Bubble

Abstract:

The reduction of CO₂ emission as the greenhouse gas emitted in the largest volume due to human activities has become a primary focus in the last decade. Generally, in CO₂ gas purification technologies using chemical/physical absorption, the regeneration of solvent is carried out on high temperature and low pressure. This process is quite energy intensive and solvent consuming due to the evaporation loss. The ultrasonic insonation of the solution as a pioneering degassing operation promotes the developing of gas bubbles via rectified diffusion. In the physical models appeared in literature, the effect of the dissolution process on the bubble dynamics is usually neglected due to the different order of magnitudes of the respective timescales. This allows of using constant bubble mass in the equation of motion. Our investigated cases correspond to three different drive frequencies with both coupling and decoupling model settings. Numerical calculations are carried out for an adiabatic CO₂ microbubble by applying a spectral collocation method with Chebyshev polynomials. The obtained results pointed out an enhancement of the rectified diffusion rate by increase of the acoustical frequency at certain pressure amplitude. In addition, the damping effect of the mass diffusion process on the eigen-frequencies can be established in case of subharmonic-and close-to resonance cases. Nomenclature

• Periodical: Defect and Diffusion Forum (Volumes 334-335)
• Pages: 207-212
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.334-335.207
• Online since: February 2013
• Authors: Károly Czáder, Gábor K. Szabó
• Keywords: Coupled Mass Transport, Gas Scrubbing, Rayleigh-Plesset Equation

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