Filtered sub-grid constitutive models for fluidized gas-particle flows constructed from 3-D simulations

Journal Article · Sat Oct 01 00:00:00 EDT 2016 · Chemical Engineering Science

DOI:https://doi.org/10.1016/j.ces.2016.06.023· OSTI ID:1340849

Sarkar, Avik; Milioli, Fernando E.; Ozarkar, Shailesh; Li, Tingwen; Sun, Xin; Sundaresan, Sankaran

The accuracy of fluidized-bed CFD predictions using the two-fluid model can be improved significantly, even when using coarse grids, by replacing the microscopic kinetic-theory-based closures with coarse-grained constitutive models. These coarse-grained constitutive relationships, called filtered models, account for the unresolved gas-particle structures (clusters and bubbles) via sub-grid corrections. Following the previous 2-D approaches of Igci et al. [AIChE J., 54(6), 1431-1448, 2008] and Milioli et al. [AIChE J., 59(9), 3265-3275, 2013], new filtered models are constructed from highly-resolved 3-D simulations of gas-particle flows. Although qualitatively similar to the older 2-D models, the new 3-D relationships exhibit noticeable quantitative and functional differences. In particular, the filtered stresses are strongly dependent on the gas-particle slip velocity. Closures for the filtered inter-phase drag, gas- and solids-phase pressures and viscosities are reported. A new model for solids stress anisotropy is also presented. These new filtered 3-D constitutive relationships are better suited to practical coarse-grid 3-D simulations of large, commercial-scale devices.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1340849
• Report Number(s): PNNL-SA-113106; AA9010100
• Journal Information: Chemical Engineering Science, Vol. 152; ISSN 0009-2509
• Publisher: Elsevier
• Country of Publication: United States
• Language: English