The Ansys Model Fuel Library (MFL) is a library of detailed and validated reaction mechanisms for over 60 fuel components, which are relevant to combustion simulations in a wide variety of industrial and commercial applications. The fuel components can be used to represent gaseous or liquid fuel combustion for petroleum-derived or alternative fuels. Gaseous components address natural gas, synthetic gas, biofuels, and blends. For liquid fuels, the fuel components can be used in formulating surrogates for a wide range of real-world fuels, including gasoline, diesel, jet-fuel, alternative fuels, fuel blends, and additives.

The reaction mechanisms are suitable for many combustion applications, including spark-ignition engines, compression-ignition engines, gas- and liquid-fired turbine combustors, boilers, flares, and furnaces. The mechanisms have been extensively validated for operating conditions covering a wide range of pressures, temperatures, equivalence ratios, and dilutions. The mechanisms are constructed in a self-consistent manner and follow a rate-rule–based approach for liquid components that results in predictive capabilities for the mechanisms. The predictive capabilities of library mechanisms are not limited to combustion characteristics of the fuels, but also include fuel effects on emissions and combustion intermediates, along with soot particle size and number densities. The Model Fuel Library is based on both the outcome of the industry-driven Model Fuel Consortium (2006-2012) project and the ongoing Model Fuel Library Subscription Service that maintains the Library to keep it up-to-date with the state of current combustion science.

The current Model Fuel Library offering is encrypted for use with Ansys software, including Chemkin, Reaction Workbench, Forte, and Fluent (starting with version 16.0). With the Model Fuel Library, it is possible to model most real fuels by either exactly representing the chemical properties of the fuel or by formulating an appropriate surrogate. We recommend using Ansys Chemkin/Reaction Workbench to formulate surrogates for liquid fuels and also for reducing the full reaction mechanism to provide smaller mechanisms that can be tailored for a particular application (for example, for use in Computational Fluid Dynamics engine simulation).

In addition to the “full” mechanisms, the MFL provides a suite of pre-reduced mechanisms that have been reduced for specific applications and specific fuel compositions. These pre-reduced mechanisms can be used without modification for many applications, or can serve as a starting point for further reduction using a narrower range of operating conditions. In addition, PERK mechanisms installed under the MFL folder may be of interest, as these are developed to keep the mechanism size small while enabling the ability to capture a broader range of conditions than with models containing global reaction steps (see MFL Pseudo-Elementary Reaction Kinetics (PERK) Mechanisms).

The .inp file associated with an MFL mechanism includes both the species thermodynamic data and the reaction mechanism. Ansys Fluent provides a check box to indicate that the thermodynamic data is included in this way (see The Import CHEMKIN Format Mechanism Dialog Box for Volumetric Kinetics in the Fluent User's Guide).

Table 1.1: Components in the Model Fuel Library shows the list of surrogate components available in the MFL database.

Ratings of each of the available component mechanisms are listed in the following section. These ratings are qualitative. They summarize both the accuracy of the mechanism based on validation against fundamental kinetics data and our assessment of the expected predictive capabilities of that component mechanism. In some cases, the assessment is limited by availability of appropriate experimental data for validation. Also discussed in the next chapter is the applicability of those components in formulating surrogates for various fuels.

The documentation is now separate for:

An appropriate MFL full or a pre-reduced mechanism for the tailored fuel model can further be reduced using the targeted mechanism reduction capability in Ansys Chemkin Reaction Workbench. Refer to the Reaction Workbench Tutorial Guide and Mechanism Reduction Best Practices for more information.