(203d) Comparison of Modeling Methodologies for Simulating a Gassed-Agitation System with Experimental Validation

Aerobic and microaerobic fermentation processes require significant aeration for proper organism performance in both stirred tanks and air-lift columns. In stirred tanks, the power requirement for agitation is an important design parameter that indirectly relates back to bulk mass transfer coefficient kLa. Recent work has shown that simulations predict kLa and that breakup and coalescence are essential for predicting the agitator power in gassed stirred tanks. Three methods are available for modeling gas/liquid flow in an agitated vessel: full-resolution of the gas/liquid interface; lagrangian particle tracking of all bubbles; and a lagrangian-parcel approach, where groups or parcels of bubbles are modeled collectively. For the later two methods, there is in addition a choice of how to model breakup and coalescence. This work will compare simulation and experimental results to assess how well these various methods predict the power in a gassed-agitated system, with a specific emphasis on the impeller flooding.