Abstract
In this paper we shortly investigate the similarity between states for different fluidized bed regimes, which is an essential requirement for the application of recurrence computational fluid dynamics (rCFD) [Lichtenegger and Pirker, Chem. Eng. Sci. 153, 394 (2016)]. Therefore, bubbling and turbulent fluidization regimes are outlined in the frame of different variable-based recurrence/distance norms (rNorm/dNorm). This last is typically used to quantify the degree of flow similarity within the observation time span. The recurrence plots or the so-called recurrence/distance matrices are accordingly constructed upon the rNorm/dNorm values and show no recurrence tendency for the full-resolved turbulent fluidization regimes. It is reported thereabouts that the high fluctuated nature of turbulent fluidization (interphase small scales) absentees the periodicity, and a disclosing procedure for the superstructure (large-scale) dynamics is vitally needed. To that end, a spatial filtering with the idea of the domain decomposition (recurrence island) has been applied to reveal a proper posterior indicator of turbulent fluidization recurrence. The filtering approach handles in increasing the recurrence prominence without changing the system behavior and makes the recurrence more visible. From other perspectives, a turbulence modeling using the coarse-grained approximate deconvolution model–two-fluid model (ADM-TFM) is employed for the turbulent fluidization case. Following its recurrence investigations, the resultant prominence offered by ADM-TFM is in a very comparable aspect to the same grid spatial filtering.
8 More- Received 10 November 2020
- Accepted 2 April 2021
DOI:https://doi.org/10.1103/PhysRevFluids.6.044310
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