Simulations that challenge reality

AVL FIRE™ 2019 R2 and AVL FIRE™ M 2019 R2

Find out about the latest releases of FIRE and FIRE M

AVL FIRE™ is the leading computational fluid dynamics (CFD) software package. It is designed to simulate gas exchange, fuel injection, ignition, combustion, emission formation and heat transfer in internal combustion engines. AVL FIRE M brings the power of this tool to multi-domain modelling scenarios. Both, FIRE and FIRE M are designed to solve the most demanding flow problems in respect to geometric complexity, physics and chemistry.

Now, with the release 2019R2, FIRE and FIRE M have received an upgrade. Refinements and new features extend the existing functionalities of both of these tools, bringing extra value to your simulation workflow.



Main Program

Embedded Body

A new feature, called Embedded Body simplifies the modeling of geometrically complex bodies and otherwise difficult to handle moving boundaries dramatically. It uses a different approach to the traditional mesh generation process of Finite-Volume CFD Codes that relies on boundary-fitted grids. Instead the Embedded Body approach requires a simple background grid for the enclosing domain, while any insert needs to be present as CAD Model only.

During run time the software sorts out the relation of each individual computational cell of the background grid to the body (or bodies). At every time step it asks and answers the questions of a cell part of it or not, and the right equations are solved respectively.

Embedded Body therefore simplifies and shortens the pre-processing time especially for models representing complex shapes or involving rotating or otherwise moving parts. As 2019 R2 offers Embedded Body only in conjunction with non-reacting single-phase flows, it is ideal for applications such as fans, blowers, turbo-chargers and pumps.

Adaptive Mesh Refinement with Embedded Body

The quality of simulations deploying the Embedded Body technology strongly depends on grid resolution near the body’s surface. A simple way to ensure appropriate computational mesh is with Adaptive Mesh Refinement. This can be applied with FIRE M 2019 R2 in combination with embedded bodies. The implementation resolves the body surface continuously, in case the body surface is changing.


The Monte Carlo radiation model that was implemented in FIRE M v2018.1 has been extended in 2019 R2 to work with multi-domain models. It is designed for the analysis of surface-to-surface radiation with a transparent media between the surfaces. To reduce the calculation time, this new model clusters surface elements, increasing the performance on large and complex geometries.

Analytical Wall Function for Heat Transfer

The Analytical Wall Function for heat transfer (denoted as AWF-e) is a new feature in FIRE M 2019 R2. It operates in conjunction with the main flow and turbulence computed with the k-ζ-f turbulence model that includes the Hybrid Wall Treatment.

This modeling strategy has been validated in several benchmarks involving representative pipe flows with strong temperature gradients and fluid property variations.

Its applicability has also been proven with the more complex flow configurations such as ICE and e-motor cooling jacket models. The results confirm reduced mesh sensitivity and superiority of the AWF-e approach compared to other conventional approaches.


PEM Fuel Cell Model in FIRE M

This latest release of FIRE M allows the computing of low-temperature PEM fuel cells, and takes advantage of FIRE M’s pre and post-processing capabilities. The model now available in FIRE M includes a new catalyst layer and aqueous ionomer material groups. It provides a user-friendly GUI guiding the user through the setup of the simulation case. Additionaly it offers an extended property database (PDB) with new material groups and properties.

The FIRE M PEMFC Solution enables solving of the following:

  • Gas and liquid water in flow channels and porous channels, such as gas diffusion layers and catalyst layers, including capillary effects
  • Gas species in flow channels and porous layers, including multi-component diffusion
  • Dissolved water in the ionomer phase (catalyst layer, membrane)
  • Dissolved gas species in the ionomer phase enabling gas transport across the membrane (gas crossover)
  • Reactants (O2, H2) in the agglomerates (catalyst layer)
  • Electrons in all conducting solids (bipolar plates, gas diffusion layers, catalyst layers)
  • Ion in the ionomer phase
  • Heat in all phases – gas, liquid and solid

Transient PEM Fuel Cell Simulation

PEM fuel cells can now be simulated under transient operating conditions, e.g. load jumps or cycles. The most important transient phenomena in PEM fuel cells are the hydration/dehydration of the membrane in conjunction with the water sorption/desorption in the catalyst layers. Other important transient phenomena include the gas dynamics in the flow channels and porous media, as well as the liquid water transport in channels and porous media.





Different Coating Zones in the Filter Wall

In this latest release, it is possible to select three different catalytic coating positions in the filter wall – top, bottom and extruded. Regeneration and catalytic reactions taking place simultaneously and in the same position on the filter wall are now considered.


Spray / Combustion

Stretch Rate for FSD-Transport Equation

For pre-chamber engine combustion simulations, the stretch rate of the production term of the flame surface density equation must be adopted based on the Karlovitz number. With FIRE 2019 R2 the adaptation is performed on the fly during the simulation.

Update of the TABKIN / FGM model

FIRE 2019 R2 also includes an update to TABKINTM / FGM. This update features:

  • Improved handling of emission models
  • More realistic description of the spark ignition process for applications which feature premixed combustion
  • The AVL proprietary reaction scheme can be applied for table generation

Water/Gasoline Injection and Combustion

FIRE 2019 R2 includes advancements to the modules for spray and wallfilm, as well as species transport and combustion. These adaptations are designed to cover the simultaneous injection of gasoline and water into the engine’s cylinder. Further output qualities have been made available at the same time. This is to provide more insight into both the physical and chemical processes involved.