A new operating mode of NETmix for active mixing under batch operation

Abstract

NETmix is a mesoscale static mixer comprising cylindrical chambers interconnected by prismatic channels. Efficient chaotic mixing is typically achieved above a critical Reynolds number. However, reaching this threshold requires increased flow rates, which reduce residence time, a limitation often addressed by fluid recirculation in multiple passages. This study introduces O-NETmix technology, enabling active mixing under batch operation with high mixing intensities without fluid recirculation. Using CFD models, the influence of injected volume per oscillation was analysed for four oscillatory Reynolds numbers. Tracer distribution simulations demonstrated that chaotic mixing is achievable even below the critical Reynolds, identifying optimal oscillatory parameters for each Reynolds number, where mixing occurs more rapidly. A key factor is the ratio of injected volume per oscillation to chamber volume, with an optimal value of approximately 38 % for this geometry. The O-NETmix technology offers significant potential for applications requiring long residence times, such as emulsification processes and crystallisation.