Particle Separation Efficiency Experiments in Single and Arrayed Vortex Tube Separator (VTS) Configurations

This study investigates how particle separation efficiency behaves differently in a single central vortex tube separator (VTS) tube operating in isolation compared to when it functions as part of a multi-tube array. Specifically, it aims to establish the sensitivity of separation performance to array-induced aerodynamic effects by examining the mechanisms responsible for observed differences between the canonical single-tube and seven-tube configurations. Using a custom-designed particle separation rig, a wide range of test dusts with standardized military and industrial specifications were tested for separation efficiencies. For ISO 12103-1 A4 Coarse Dust, the 7VTS configuration exhibited a significantly lower mean separation efficiency (74.73±1.23%) compared to the 1CVTS (83.36±1.62%). This trend was consistent across other fine-particle distributions: AFRL 03 and ISO-A3 Medium showed 66.60±2.14% and 68.70±3.11% efficiency, respectively, in 7VTS. In contrast, larger particles such as MIL-E-5007C and Sieved Quartz achieved 88.13±1.39% and 86.85±3.15%, respectively, with smaller differences between the two configurations, where for the 1CVTS case, MIL-E-5007C achieved 89.46±0.87%. Results show that the single VTS achieves higher separation efficiencies than the array. The study provides compelling evidence for substantial loss of particle separation efficiency when tubes are integrated into arrays, begging further detailed study to understand and optimize array configurations. To better predict separation behavior across diverse particle types, an effective Stokes number framework was additionally developed, incorporating nonlinear drag behavior and shape corrections through empirically derived drag models.