Coupling of Traditional Chemical Engineering Mass Transfer Correlations with CFD Data: a Case Study of the Wave Bioreactor

In complex systems, calculation of mass transfer coefficients isn't as simple as calculating the Reynolds number. The Wave Bioreactor is a perfect example of a system that has a time varying velocity and surface area of mass transfer. Therefore, prediction of Kla is difficult. We present a method whereby a computational fluid dynamics (CFD) model is used to calculate both the time varying velocity and interfacial area fluctuations caused by the movement of a 1L Wave Bioreactor. This is accomplished by using the Volume of Fluid model in Fluent 6.3 to track the air-water interface, as well as, determine the velocity at that interface. The model predicts the onset of air entrainment at 30-35 rpm due to crashing waves which is validated by experimental data. Finally, Kla measurements were performed on the Wave Bioreactor to generate the necessary data to correlate the CFD outputs.