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Title: Development of a Two-fluid Drag Law for Clustered Particles using Direct Numerical Simulation and Validation through Experiments

Abstract

This study presents a new drag model, based on the cohesive inter-particle forces, implemented in the MFIX code. This new drag model combines an existing standard model in MFIX with a particle-based drag model based on a switching principle. Switches between the models in the computational domain occur where strong particle-to-particle cohesion potential is detected. Three versions of the new model were obtained by using one standard drag model in each version. Later, performance of each version was compared against available experimental data for a fluidized bed, published in the literature and used extensively by other researchers for validation purposes. In our analysis of the results, we first observed that standard models used in this research were incapable of producing closely matching results. Then, we showed for a simple case that a threshold is needed to be set on the solid volume fraction. This modification was applied to avoid non-physical results for the clustering predictions, when governing equation of the solid granular temperate was solved. Later, we used our hybrid technique and observed the capability of our approach in improving the numerical results significantly; however, improvement of the results depended on the threshold of the cohesive index, which was usedmore » in the switching procedure. Our results showed that small values of the threshold for the cohesive index could result in significant reduction of the computational error for all the versions of the proposed drag model. In addition, we redesigned an existing circulating fluidized bed (CFB) test facility in order to create validation cases for clustering regime of Geldart A type particles.« less

Authors:
; ;
Publication Date:
Research Org.:
Florida International Univ. (FIU), Miami, FL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1191170
DOE Contract Number:  
FE0007260
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English

Citation Formats

Gokaltun, Seckin, Munroe, Norman, and Subramaniam, Shankar. Development of a Two-fluid Drag Law for Clustered Particles using Direct Numerical Simulation and Validation through Experiments. United States: N. p., 2014. Web. doi:10.2172/1191170.
Gokaltun, Seckin, Munroe, Norman, & Subramaniam, Shankar. Development of a Two-fluid Drag Law for Clustered Particles using Direct Numerical Simulation and Validation through Experiments. United States. https://doi.org/10.2172/1191170
Gokaltun, Seckin, Munroe, Norman, and Subramaniam, Shankar. 2014. "Development of a Two-fluid Drag Law for Clustered Particles using Direct Numerical Simulation and Validation through Experiments". United States. https://doi.org/10.2172/1191170. https://www.osti.gov/servlets/purl/1191170.
@article{osti_1191170,
title = {Development of a Two-fluid Drag Law for Clustered Particles using Direct Numerical Simulation and Validation through Experiments},
author = {Gokaltun, Seckin and Munroe, Norman and Subramaniam, Shankar},
abstractNote = {This study presents a new drag model, based on the cohesive inter-particle forces, implemented in the MFIX code. This new drag model combines an existing standard model in MFIX with a particle-based drag model based on a switching principle. Switches between the models in the computational domain occur where strong particle-to-particle cohesion potential is detected. Three versions of the new model were obtained by using one standard drag model in each version. Later, performance of each version was compared against available experimental data for a fluidized bed, published in the literature and used extensively by other researchers for validation purposes. In our analysis of the results, we first observed that standard models used in this research were incapable of producing closely matching results. Then, we showed for a simple case that a threshold is needed to be set on the solid volume fraction. This modification was applied to avoid non-physical results for the clustering predictions, when governing equation of the solid granular temperate was solved. Later, we used our hybrid technique and observed the capability of our approach in improving the numerical results significantly; however, improvement of the results depended on the threshold of the cohesive index, which was used in the switching procedure. Our results showed that small values of the threshold for the cohesive index could result in significant reduction of the computational error for all the versions of the proposed drag model. In addition, we redesigned an existing circulating fluidized bed (CFB) test facility in order to create validation cases for clustering regime of Geldart A type particles.},
doi = {10.2172/1191170},
url = {https://www.osti.gov/biblio/1191170}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Dec 31 00:00:00 EST 2014},
month = {Wed Dec 31 00:00:00 EST 2014}
}