The prediction of two-phase fluid-solid (gas-solid and liquid-solid) flow remains a major challenge in many engineering and industrial applications. Numerical modeling of these flows is complicated and various studies have been conducted to improve the model performance. In the present work, the two-fluid model of Bolio et al. (1995), developed for dilute turbulent gas-solid flows, is employed to investigate turbulent two-phase liquid-solid flows in both a vertical pipe and a horizontal channel. <p>Fully developed turbulent gas-solid and liquid-solid flows in a vertical pipe and liquid-solid (slurry) flow in a horizontal channel are numerically simulated. The momentum equations for the fluid and solid phases were solved using the finite volume technique developed by Patankar (1980). Mean and fluctuating velocities for both phases, solids concentration, and pressure drop were predicted and compared with the available experimental data. In general, the mean velocity predictions for both phases were in good agreement with the experimental data for vertical flow cases, considered in this work. <p>For dilute gas-solid vertical flows, the predictions were compared with the experimental data of Tsuji et al. (1984). The gas-phase fluctuating velocity in the axial direction was significantly under-predicted while the results for the solids fluctuating velocity were mixed. There was no data to compare the solids concentration but the profiles looked realistic. The pressure drop was observed to increase with increasing Reynolds number and mass loading when compared with the data of Henthorn et al. (2005). The pressure drop first decreased as particle size increased and then started increasing. This behaviour was shown by both experimental data and model predictions. <p>For the liquid-solid flow simulations the mean velocity profiles for both phases, and the liquid-phase turbulence kinetic energy predictions (for dilute flow case), were in excellent agreement with the experimental data of Alejbegovic et al. (1995) and Sumner et al. (1990). The solids concentration profiles were poorly predicted, especially for the lighter particles. The granular temperature profiles, accounting for the solids velocity fluctuations, for the dilute flow case failed to agree with the data, although they captured the overall trend. The liquid-solid pressure drop predictions, using the present model, were only successful for some particles. <p>The solids concentration predictions for the horizontal flow case were similar to the experimental measurements of Salomon (1965), except for a sharp peak at the bottom wall and the opposite curvature. The mixture velocity profiles were asymmetric, due to the addition of particles, and were similar to the experimental data, though only a partial agreement was observed between the predictions and the data.<p>A conclusion from this work is that the present model, which was developed for dilute gas-solid flows, is inadequate when liquid-solid flows are considered. Further improvements, such as including the interstitial fluid effects while computing the liquid-phase stress, are needed to improve the predictive capability of this two-fluid model.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-05282007-225547 |
| Date | 29 May 2007 |
| Creators | Yerrumshetty, Ajay Kumar |
| Contributors | Sanders, R. Sean, Bugg, James D., Bergstrom, Donald J., Sumner, David |
| Publisher | University of Saskatchewan |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-05282007-225547/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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