Aerosol Entrainment from a Sparged Non-Newtonian Slurry

Abstract

Previous bench-scale experiments have provided data necessary for the development of empirical models that describe aerosol entrainment from bubble bursting. However, previous work has not been extended to non-Newtonian liquid slurries. Design of a waste treatment plant on the Hanford Site in Washington required an evaluation of the applicability of these models outside of their intended range. For this evaluation, aerosol measurements were conducted above an air-sparged mixing tank filled with simulated waste slurry possessing Bingham plastic rheological properties. Three aerosol-size fractions were measured at three sampling heights and for three different sparging rates. The measured entrainment was compared with entrainment models. One model developed based on bench-scale air-water experiments agreed well with measured entrainment. Another model did not agree well with the measured entrainment. It appeared that the source of discrepancy between measured and modeled entrainment stemmed from application beyond the range of data used to develop the model. A possible separation in entrainment coefficients between air-water and steam-water systems was identified. A third entrainment model was adapted to match experimental conditions and fit a posteri to the experimental data, resulting in a modified version that resulted in estimated entrainment rates similar to the first model.

Literature survey of droplet entrainment from water pools

“…The modified Kataoka (Fritz, 2006) and Rozen et al (1970) correlations and the measured entrainment show no dependence on sampling height above the water pool in the deposition-controlled region. It was also observed in previous THAI experiments (TH25), as shown in Fig.…”

“…The behaviour of the fluid depends on the shear stress, and it has a threshold value where the non-Newtonian fluid behaves like a Newtonian fluid. Fritz (2006), simulated the radioactive wastes from the Hanford site in Washington that are stored in underground tanks. The clean-up strategy is to retrieve the liquid slurry waste from the tanks and stabilize it by glassification at a Waste Treatment Plant (Gephart and Lundgren, 1995).…”

“…This means that the Sterman's model to calculate the gas volume fraction is valid (Sterman, 1957). (Fritz, 2006) and Rozen correlation (Rozen et al, 1976b) in the deposition controlled region under a bubbly flow regime.…”

“…12. Comparison of measured entrainment and modified Kataoka and Ishii correlation(Fritz, 2006) and Rozen correlation(Rozen et al, 1976b) in the deposition controlled region under a bubbly flow regime.…”