NUMERICAL SIMULATION OF TWO-PHASE FLOW DYNAMICS IN COUNTER-CURRENT SWIRL SEPARATORS: MULTIFACTOR ANALYSIS OF GEOMETRIC AND OPERATIONAL PARAMETERS

This paper addresses efficiency optimization of centrifugal gas cleaning from fine particulate matter (PM2.5) in cyclone-type devices utilizing two opposing swirled flows. To unify various literature terms describing this hydrodynamic scheme – such as dual-vortex, opposed-swirl, or counter-current swirl configurations – we propose the comprehensive term “Counter-Current Swirl Separators” (CCSS). A defining physical feature of CCSS is the introduction of an axially swirled lower inlet stream that directly interacts with the upper vortex structure. The separation characteristics of the apparatus were evaluated using a combined computational and statistical approach. This methodology relies on a multi-factor design of experiments. In particular, a dataset of 60 numerical runs was generated via a maximin Latin Hypercube Sampling (Maximin LHS) strategy. This space-filling design provided data for a multi-dimensional sensitivity analysis. The cut-off diameter d50 was selected as the main objective function. The analysis covered joint variations of six key geometric and operational para- meters. As a result, the investigated factors were quantitatively ranked by their impact on fractional efficiency. The approach also revealed hidden masking effects and localized regions of non-linear system behavior during the vortex interaction. A comprehensive technical and economic criterion was introduced to evaluate the apparatus performance. This approach establishes a mathematical foundation for subsequent multi-objective optimization of the separator geometry. The resulting Pearson and Spearman correlation matrices confirm a predominantly monotonic response of the system within the studied ranges. These matrices define the validity boundaries for future continuous surrogate modeling.