Study On The Bubble Formation In Non-Newtonian Fluid

The bubble behavior in non-Newtonian fluid plays a key role in such diverse fields as waste water treatment, petroleum processing, fermentation, polymer devolatilization, composites processing, boiling, plastic foam processing and environment remediation. Polyacrylamide(PAM) is widely applied in industrial processes and biomedicine material; its foundational characteristic has been sufficiently understood. In this paper, PAM aqueous solution was used to study the behavior of bubble formation as non-Newtonian fluid.Density, surface tension and rheological characteristics are the essential properties of the non-Newtonian fluid. Pycnometer, surface tensiometer, and rheometer were adopted respectively to measure the density, surface tension and rheological characteristics of 0.25% (wt), 0.50% (wt), 0.75% (wt) PAM aqueous solutions at 293.15K. The parameters of equations were fitted in terms of the experimental data.A laser measurement system for studying the behavior of bubble formation was established. The bubble formation in PAM aqueous solutions at 293.15K was measured by the use of a CCD camera, computer picture collection and treatment technique. The effects of rheological characteristics, orifice diameter, chamber volume and gas flowrate on detachment volume of bubble were investigated respectively.A model of bubble formation, which consists of the radial expansion equation and the vertical ascension equation of bubble interface under constant flowrate conditions, was developed combining continuity equation, motion equations of hydromechanics with rheological equation of non-Newtonian fluid. The model was employed to calculate the bubble size and detachment volume during its formation in different concentration PAM aqueous solutions, orifice diameters and chamber volumes. The effects of rheological characteristics, orifice diameter, chamber volume and gas flowrate on bubble formation were discussed. The results show that rheological characteristics, orifice diameter, and gas flowrate influences bubble formation significantly, whereas the effect of chamber volume is unconspicuous. The...