EBI-DNScode

Major Update for EBI-DNS (July 2024)

We are excited to announce the new version of EBI-DNS! Since 2012, EBI-DNS provides a coupling between OpenFOAM and Cantera to enable the use of accurate diffusion models together with efficient chemistry integration. There have been major updates and improvements in this update as detailed below:

• Code updated to the latest OpenFOAM versions (v2312 and v2406), taking advantage of new HPC developments in the ESI OpenFOAM version
• Update of the internal Cantera version to the latest version 3.1.0a2
• Coupling library re-written from scratch to fully integrate with OpenFOAM’s infrastructure, allowing the optional use of turbulence models, radiation models, post-processing tools…
• In addition to mixture-averaged and multicomponent diffusion, new options for the diffusion models are:
  • Support for accurate thermo diffusion (Soret effect) together with the mixture-averaged transport model (e.g. for hydrogen modeling)
  • Unity Lewis number and species-specific Lewis numbers
  • Sutherland model
• New optional low-Mach model to decouple hydrodynamic and thermodynamic pressure
• Support for adaptive mesh refinement (AMR) and moving meshes
• Improved the stability for ODE integration with CVODE and added more options to speed-up the integration process
• New boundary conditions for burner-stabilized flames and zero-species flux to ensure physical results when Soret diffusion is activated
• Support for Lagrangian particle tracking, e.g. to model spray evaporation and liquid fuels
• Support for differently formulated energy equations in terms of
  • Sensible enthalpy
  • Absolute enthalpy
  • Sensible internal energy
  • Absolute internal energy
  • Temperature
• Optional inclusion of kinetic energy, viscous dissipation and potential energy in the specified energy equation
• New model for radiation assuming optically thin gases
• Pressure-velocity coupling available based on compressibility (phi) and density (rho) supported as well as pressure (p) and hydrostatic pressure (p_rgh)
• All versions of Sundials supported (from 2.7.0 to the latest version 7.0.0), with and without LAPACK
• Optional pressure offset to increase the numerical accuracy of the hydrodynamic pressure field
• Implementation of species-specific turbulent Schmidt numbers
• New utility to interpolate 1D flame profiles generated with Cantera to any OpenFOAM simulation domain
• Updated the internal version of Eigen to 3.4.90
• Improved formulation to calculate the Fourier number which is now valid in 2D and 1D cases
• New function object for sponge regions to filter out unphysical pressure oscillations
• Use of either convective CFL or acoustic CFL number for time step control
• Fully compatible with OpenFOAM compiled with 32 and 64 bit labels as well as double and single precision floating points
• Fully compatible with Sundials compiled with 32 and 64 bit integers as well as double and single precision floating points
• Extended the documentation with more best-practice tips and detailed descriptions how to install and update existing cases
• Even though Cantera has added additional external dependencies in the latest versions, the only external dependency for EBI-DNS is Sundials, making the installation easy even on older or less common systems. Installation tested with gcc, Clang, Intel icc and Intel icx compilers.

Recent examples of work done with EBI-DNS include:

1. T. Zirwes, M. Sontheimer, F. Zhang, A. Abdelsamie, F. E. Hérnandez Pérez, O. T. Stein, H. G. Im, A. Kronenburg, and H. Bockhorn, “Assessment of numerical accuracy and parallel performance of OpenFOAM and its reacting flow extension EBIdnsFoam,” Flow, Turbulence and Combustion, vol. 111, pp. 567–602, 2023. (https://doi.org/10.1007/s10494-023-00449-8)
2. T. Zirwes, S. Eckart, F. Zhang, T.L. Kaiser, K. Oberleithner, O.T. Stein, H. Bockhorn and A. Kronenburg, "Structure and dynamics of hexagonal cells in H2/CO2 flames," Proceedings of the Combustion Institute, vol 40, 2024. (https://doi.org/10.1016/j.proci.2024.105332)

If you have any questions, please contact vbt-openfoam(∂)ebi.kit.edu or the main developer, Thorsten Zirwes, directly
(thorsten.zirwes(∂)itv.uni-stuttgart.de).

Description of EBI-DNS

OpenFOAM^® is a widely used, flexible, easy to extend and powerful toolkit for computational fluid dynamics simulations that provides additional tools for pre and postprocessing. It has a number of solvers dedicated to the simulation of combustion processes. These solvers suffer from some shortcomings:

• No detailed models for molecular diffusion are available. Instead, a unity Lewis number is assumed for all species.
• The computation of chemical reaction rates from finite rate models uses OpenFOAM's^® solvers for ordinary differential equations (ODE). Compared to other ODE solvers, they run much slower.

In order to overcome these shortcomings and to provide an OpenFOAM^® based solver that can compute flames both accurately as well as efficiently, the EBI-DNS solver was created. It was first developed in 2012 and has been improved ever since. It couples OpenFOAM^® to the open-source library Cantera. This enables the use of Cantera's detailed model for diffusion coefficients. This also means that reaction mechanisms can be provided to the OpenFOAM^® solver in Cantera's xml format. The integration of chemical reaction rates is performed by Sundials CVODE solver, which is the only third-party dependency of the EBI-DNS solver. Compared to OpenFOAM's^® own ODE solvers, this was found to speedup chemistry computation by a factor of ten, depending on the setup.