In the CFD prediction of gas hold up in gas-liquid STR, it is necessary to take into account the observation that turbulence increases the effective drag felt by gas bubbles thereby reducing their rise velocity. This can be done by the Brucato correlation.
In gas-liquid-liquid CFD predictions (where a viscous 2nd dispersed phase is treated through mixture properties), the use of the Brucato correlation leads to a decrease in effective contribution to drag by turbulence (through the calculation of the kolmogorrof's length scale based on kinematic viscosity). This seems to be in contradiction with accepted theory that droplets lead to increased turbulence in the system (as modelled by for example the Sato approach).
How does one go about resolving this?
As per me this need a UDF is needed to exactly trace bubble break and energy release prediction need a careful consideration of molecular level and Input data need to be predicted on Kolmogorov microscales, and interpretation with knudsen number gives a positive results.
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