Turbulent particle-laden flows are of high interest due to their presence in many sectors of industry. High Reynolds number flows with solid particles entrained within, create complex flows and erosive environments. The effect that the particles have on the turbulence of the surrounding fluid is referred to in the literature as turbulence modulation. Turbulence modulation is an area of research where there is still much to learn to better understand the physics behind these incredibly complex flows. Data that would be of particular usefulness are at higher Reynolds numbers (Re\<100,000), and dense loadings (*φ~V~* \> 1%). Turbulent particle-laden flow through a simplified industrial geometry was studied at an upper Reynolds number of 115,000 and particle loadings up to 5% by weight/volume (specific gravity = 1) to address these needs. The flow within a tee junction with the 90-degree branch closed-off downstream was studied. This is analogous to a duct flow but with a free-shear layer interacting with the surface of the fluid at the entrance to the closed-off leg. Super absorbent particles were used as the solid phase, which became index-matched and neutrally buoyant upon saturation with water. This allowed for optical access into the test section. Data were acquired using 2-D planar particle image velocimetry (PIV). Mean and root-mean-square (rms) velocities were calculated for the continuous phase based on 2,000 instantaneous correlations. Particle loadings studied were 0%, 1%, 3%, and 5% by. These dense levels of particle loadings were made feasible by the closeness of the index matching. A Reynolds number of 11,500 was studied along with 115,000 for an additional basis of comparison. Velocity contour plots are presented to provide a macro description of the flow. These provided the visualization of the turbulent duct flow and the slowly recirculating flow in the 90-degree bend. Several horizontal positions upstream and downstream of the bend are presented for a more detailed discussion. Parameters that are used in the literature to predict turbulence modulation were calculated and they suggested that attenuation would occur as a result of the addition of the particles. The experimental data at the various positions showed that the mean velocities were nominally unaffected. The rms velocities did show localized sensitivity off the centerline of the flow but were much less drastic than expected. The effect that the particles had on the flow was also sensitive to the Reynolds number, as there were examples where weakening of the rms was observed in the low Reynolds number case, and strengthening in the high Reynolds number case for the same particle loading in the same region of the geometry.  


Effect of Neutrally Buoyant Particles on Horizontal Turbulent Flow Through a Tee-Junction

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.