On the mixing in confined impinging jet mixers - Time scale analysis and scale-up using CFD coarse-graining methods

Therefore, this contribution tackles this sensitive topic using experimentally validated computational fluid dynamics (CFD) calculations. Thereby, mixing times are extracted from CFD using the spatially and temporally reduced numeric measurement approach (STAR NM), lately presented by the authors. These mixing times, sampled over a wide range of flow rates and inherently a wide range of energy dissipation rates (10−1-107 W/kg) in a CIJM, are interpreted in the framework of classic mixing theory. Comparison to mixing times calculated with the engulfment model of mixing and some modifications such as the Global Mixing Approach are made. Based on the STAR NM data that are taken for reference, a modified mixing approach is developed that takes meso and micro time scales into account. An outlook of certain scale-up rules for CIJMs is made.