The project team will develop an accurate drag correlation for gas-solid multiphase flow that includes the effect of clustered particles. DNS and experiments will be used to develop the drag correlation. The experiments will utilize high speed imaging to capture instantaneous solid volume fraction and particle velocities in a large laboratory scale gas solid riser column. Images of the clustered particle structures will then be converted into a computational model where the detailed flow field around the particles will be resolved using DNS. The drag force correlation will then be tested in the NETL open source multiphase gas solids flow and reactions simulation software MFIX (Multiphase Flow with Interphase eXchanges) by comparing the simulation results against experimental data (pressure loss) obtained in a vertical riser.
The Historically Black Colleges and Universities and Other Minority Institutions (HBCU/OMI) Research and Development (R&D) Program within the U. S. Department ofEnergy (DOE) Office of Fossil Energy (FE) provides a mechanism for 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 and power system design.
Florida International University has won a competitive award in the HBCU/OMI program to develop a two-fluid drag law for clustered particles using experimental testing and direct numerical simulations (DNS).
Computational Fluid Dynamics (CFD) has become a valuable tool in assisting the design and optimization of gasifiers, combustors and chemical reactors using fossil fuels. Accurate closure laws are needed to capture the interaction of gas and solid phases in CFD simulation of multiphase reactors such as a coal gasifiers, and fluidized bed boilers. Interphase drag between gas and the solids plays a key role in the accurate prediction of the hydrodynamics in CFD simulation of multiphase reactors. The project will develop a new and validated drag law, which accounts for particle clustering effects, inside the reactor. This will allow scientists and engineers to more realistically simulate the hydrodynamics, gasification kinetics and thermal behavior of complex gas-particle flow systems. With more realistic simulation capability, more efficient and less costly advanced fossil energy based power generation systems can be designed and built.
An example of the particle-resolved direct numerical simulation capability is shown in Figure 2.
Goals and Objectives
The goal of the project is to develop a two-fluid drag-law for clustered particles using DNS. Specifically, the project will apply advanced experimental and computational techniques to develop and validate new drag force correlations for the case of particle clustering based on DNS of gas-solids flow structures in risers and vertical columns, and validate the proposed drag law using the MFIX multiphase flow simulation code.
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