The project team will use the DNS method to investigate the drag force between solid particles and gas phases. The advanced Lattice Boltzmann Method (LBM) will be used to carry out simulations for microscopic model systems in which the particle surface is directly resolved. The immersed boundary (IB) technique will be included in the LBM to accurately represent particle shapes in the simulation, allowing for straightforward accounting of poly-dispersed and non-spherical particles. Effects of particle rotation and of hydrodynamic interactions and direct contacts between particles will be included in the simulation. Particle motion and forces will be recorded and compared to experimental results obtained using high-speed particle imaging methods developed at NETL. The particle-fluid drag force data acquired from fine-scale simulations will be used to generate a database to help formulate an improved drag correlation that explicitly includes information on microstructures of particles and fluid flows as well as particle and fluid properties. Finally, the new drag correlation will be tested in the NETL open source multiphase gas solids flow and reactions simulation software MFIX (Multiphase Flow with Interphase eXchanges) by comparing simulation results using the new drag correlation with simulation results using existing drag models, and comparing the simulation results with published experimental data. The project team will also conduct studies to compare the new model with other traditional drag models to predict gas-solid flow interactions at mesoscopic scales.
The Historically Black Colleges and Universities and Other Minority Institutions (HBCU/OMI) Research and Development (R&D) Program within the U.S. Department of Energy (DOE) Office of Fossil Energy (FE) provides a mechanism to conduct cooperative FE R&D projects between DOE and the HBCU/OMI community. This program encourages private sector participation, collaboration, and interaction with HBCU/OMI in FE R&D; facilitates the exchange of technical information to raise the overall level of HBCU/OMI competitiveness with other institutions in the field of FE R&D; enhances educational and research training opportunities for tomorrow’s scientists by developing and supporting a broad-based research infrastructure; and helps to position HBCU/OMI graduates to enter technical and leadership roles in America’s FE industry.
The National Energy Technology Laboratory’s (NETL) Office of Coal and Power Systems supports the development of innovative, cost-effective technologies for improving the efficiency and environmental performance of advanced coal and power systems. One current focus area facilitates research to simulate the complex processes that occur within a coal gasifier or across an entire coal based chemical or power plant. This research helps scientists and engineers better understand the fundamental steps in these processes so they can more efficiently optimize coal power system design. NETL is partnering with Tuskegee University to investigate particle rotation effects in gas-solid flows using direct numerical simulation (DNS).
Completion of this project will provide a new drag model that accounts for particle rotation effects and quantitative insights into fundamental gas-solid particle interactions in flow regimes of interest to fossil energy power generation systems. The database resulting from this study will help to fill a data gap and formulate the constitutive equations necessary for more accurate Eulerian-Lagrangian multiphase flow models. These studies will eventually contribute to the design of more efficient and environmentally benign power generation systems.
Goal and Objectives
The goal of this project is to address the effects of particle rotation in gas-solid flows. Specific objectives to be studied include (1) the direct impact of particle rotation on the average particle-fluid drag force of a particle suspension at various Reynolds numbers (i.e., ratios of inertial to viscous forces); (2) the indirect impact of particle rotation on the drag force through the change in particle concentration distribution or the microstructure of a flow; and (3) the role of particle rotation in energy dissipation of a particle-fluid system.
Click to view Presentations, Papers, and Publications