Development of Software Tools
Development of MFS software tools takes place in several specialty groups within the MFS program and the work is supported by several DOE programs.
The flagship software capability is the MFiX Suite of open-source multiphase computational fluid dynamics software. NETL has maintained a multiphase flow modeling program for over 34 years, starting from when CFD was in its infancy until present day where CFD has become a well-accepted tool for studying reacting flows. NETL’s expertise in dense, reacting multiphase flow is unique and continues to be one of NETL’s and FE’s key capabilities. In the past 5 years, there has been renewed emphasis on the expansion of the MFiX family of codes to include more accurate and capable modeling approaches such as MFiX-DEM and MFiX-PIC.
The objective MFiX Suite development program is to continue enhancement of NETL’s capabilities for simulation-based engineering (SBE) of advanced chemical reactors and associated devices. Specific Goals for the effort include:
- Additional physics required for challenging reactor design applications including radiative heat transfer, non-spherical particles, intra-particle physics for macroscopic non-spherical particles;
- Enhancements to speedup code execution;
- Improvements to the graphical user interface (GUI) to increase usability of the code and to minimize error in setup, execution, and post processing;
- Expanded Quality Assurance (QA) Program including code validation, verification, improved documentation, user guides, and validation experiments.
- Enhanced outreach capabilities through the MFiX web portal to better serve FE and NETL stakeholders
The main development efforts presently underway include:
- Formal release of the new Coarse-Grained DEM code;
- Development and validation of Superquadrics DEM for non-spherical particles;
- Flow Solver Acceleration;
- Optimize and debottleneck CPU-based code;
- Port flow solver to GPU architecture
- GUI capabilities;
- Pre- and Post-processing enhancements (e.g. MFiX 20.1), including mesh generation and mesh quality assurance
To assess the prediction credibility of MFiX suite and maintain standards as an open-source scientific software, several quality assurance efforts are presently underway which include:
- Integrated Verification, Validation and Uncertainty Quantification (VVUQ) framework
- Availability of open access datasets from validation experiments to MFiX simulations, and VVUQ analysis for reproducibility and replicability in science
- Continuous regression tests (refer to V&V manual)
A DOE Exascale Computing Project (ECP) effort, led by Madhava Syamlal of the National Energy Technology Laboratory (NETL), is building a new tool, called MFiX-Exa, that will enable the needed high-fidelity simulations.
MFiX-Exa is a computational fluid dynamics–discrete element model (CFD-DEM) code designed to run efficiently on current and next-generation massively parallel supercomputing architectures. It is the latest creation based on the original MFiX code developed at NETL and is used widely in academia and industry. By combining new algorithmic approaches and a new software infrastructure, MFiX-Exa will leverage future exascale machines to optimize CLRs. Exascale will provide 50 times more computational science and data analytic application power than is possible with DOE high-performance computing systems such as Titan at the Oak Ridge Leadership Computing Facility (OLCF) and Sequoia at Lawrence Livermore National Laboratory.
Tests have shown that the new MFiX-Exa algorithm reduces the computational time for the computational fluid dynamics calculations by 4x. The new algorithm is expected to perform even better in the ECP challenge problem simulation, which will use progressively more cores on an exascale machine. Although MFiX-Exa builds on the multiphase modeling expertise embodied in NETL’s MFiX code, the core methodology has been both re-designed and re-implemented. The foundation for MFiX-Exa is the AMReX software framework supported by the ECP Block-Structured Adaptive Mesh Refinement (AMR) Co-Design Center.
MFiX-Exa uses more efficient algorithms than MFiX for reducing the computational time. A new CFD algorithm has been implemented in MFiX-Exa that leverages discretizations (finite elements of geometry) and linear solvers (pieces of mathematical software) already available through the AMReX framework. Tests have shown that the new MFiX-Exa algorithm reduces the computational time for the CFD calculations by 4x. The new algorithm is expected to perform even better in the challenge problem simulation, which will use progressively more cores on an exascale machine. MFiX-Exa recently added the capability for local mesh refinement, which enables the use of a fine mesh near the walls that accurately resolves the reactor shape while not over-refining the interior of the reactor.
C3M is a chemistry management software focused on computational modeling of reacting systems. The primary function of C3M is to provide direct links between reliable sources of kinetic information (kinetic modeling software, databases, and literature) and commonly used CFD software such as MFIX, FLUENT, and BARRACUDA with minimal effort from the user.
The software acts as a virtual kinetic laboratory to allow a CFD practitioner or researcher to evaluate complex, large sets of kinetic expressions for reliability and suitability and can interact with spreadsheet and process models. Once the chemical model is built within C3M, the software also allows the user to directly export the model to CFD software and/or a detailed report of all equations and values used to build the chemical model.