A stochastic surrogate mathematical framework to describe the distribution of species in NETmix static mixers, Chemical Engineering Journal,

This study introduces a new surrogate model to predict the distribution of species associated with a two-component single-phase flow in micro/meso-structured NETmix static mixers, aiming to find injection schemes which requires the least amount of NETmix rows to achieve a homogeneous state, thereby enabling a reduction in manufacturing costs. The NETmix’s unit cells were embedded into a lattice framework, through which the concepts of entropy and dynamic entropy were calculated by the evaluation of mass balance equations. These concepts guided a Monte Carlo simulation strategy, such that the uncertainty related to the outlet flowrate distribution on the chambers due to the typical self-sustained oscillating flow in the NETmix was captured. The strategy was validated through comparisons with computational fluid dynamics (CFD) simulations of a downwards single-phase flow in two NETmix geometries: one with four and another with eight inlet chambers. Several inlet Reynolds number (Re) conditions and tracer-water injection schemes were investigated. A better agreement between the proposed model and the CFD approach was obtained when inlet 
, a condition at which the micromixing regime of the NETmix chambers more closely corresponded to the adopted assumption of perfectly mixed flow. Therefore, the proposed approach successfully predicted the minimum number of NETmix rows required to achieve a desired species distribution for the several schemes tested.