Transport of Microparticles in a Turbulated Serpentine Passage
Quantitative, fully three-dimensional particle concentration data were obtained for a streak of ∼30 micron titanium micro-spheres injected isokinetically into the center of flow at Re = 20,000 through a ribbed serpentine passage. The rib height to channel height ratio was 10% and the pitch was 60% channel height. The ribs were oriented at 45° to the flow and staggered on opposite walls. Each passage was 10 ribs long. Concentration measurements were made using a newly developed Magnetic Resonance Imaging (MRI) based technique with an uncertainty of ±0.018% particles by volume. Three-component mean velocity data were also obtained using an existing MRI technique. The concentration data are in good agreement with the expected large-scale particle transport based on the mean flow field. Quantitative analysis is performed in the high-concentration portion of the streak where turbulent dispersion plays a significant role. Particles also tend to concentrate just upstream of the angled ribs, forming rivulets that persist as the flow returns to the channel center. These results suggest the potential for improved design of dust-resistant cooling systems based on experimental data. It is also concluded that the data set comprises a suitable validation case for Computational Fluid Dynamics (CFD) simulations.