Heat Transfer Enhancement in Agitated Reactors through Impeller Geometry Modifications: Experimental and Computational Fluid Dynamics Approaches
Abstract
This study evaluates the heat transfer behavior in agitated reactors equipped with three distinct impeller types: Two-paddle blade agitator (PBA), six-blade agitator (SBA), and helical ribbon blade agitator (RBA). A hybrid methodology combining laboratory-scale experiments and computational fluid dynamics (CFD) simulations was employed to analyze the influence of impeller geometry on thermal performance. The system comprised a 40 cm diameter stainless steel tank containing 35 liters of water, heated with a 1200 W bottom heater over an 80 min duration. CFD models using ANSYS Fluent implemented the k–ε turbulence model. Experimental results showed that the RBA impeller reached a maximum fluid temperature of 59.6 °C, outperforming SBA (54.2 °C) and PBA (47.1 °C). CFD-predicted values were in close agreement, deviating by less than 2.8% from physical measurements. The RBA also demonstrated superior thermal uniformity, with lower deviation indices and enhanced radial and axial flow patterns. A second-order polynomial regression provided excellent fit for temperature-time profiles, with coefficients of determination (R²) ranging from 0.9958 to 0.9993 across all conditions.
