(6dv) A Reduced Combustion Kinetic Model for the Methanol/Methane Dual-Fuel Engine

Research Interests: Simplification and Verification of Combustion Kinetic Model

Teaching Interests: Power
Engineering and Engineering Thermophysics

A Reduced Combustion Kinetic Model for The Methanol/Methane Dual-Fuel
Engine

Q Zhang

Institute of the Internal Combustion Engine, Xi¡¯an Jiaotong University, Xi¡¯an, Shaanxi 710049, China

Combustion reaction mechanism
is very important for three-dimensional simulation of the internal combustion
engine. At present, detailed
methane mechanisms recognized by the academic community include GRI mech 3.0. This
mechanism has 325 basic reactions and 53 species. It is applicable to the
temperature range of 1000-2500 K, the pressure range of 10 torr-10 atm, and the
equivalent ratio range of 0.1-5. But it cannot be used for the simulation of
methanol combustion process, since in this mechanism, there is less reactions
about methanol combustion. As for methanol, the mechanism of Galway University has been highly recognized. It has 173
species and 1011 reactions. This mechanism can simulate the methanol and
methane combustion process well since it contains a lot of methanol and methane
combustion reaction. However, due to the large scale of detailed mechanism, 3D
simulation process requires a lot of time. Thus, in order
to reduce the time required for simulation calculations while ensuring the accuracy
of the calculation results, a reasonable simplified chemical reaction mechanism
is needed. But simplified mechanism that can be used to simulate the
methanol/methane dual-fuel combustion process is still limited.

In this work, we follow the
basic idea of the automatic simplification method proposed by other
literatures. First, the detailed methane/methanol mechanism of Galway
University is simplified by using the direct relationship graph method which is
based on error propagation to eliminate redundant
reactants and elementary reactions. Then, using the principal component analysis
to perform secondary simplifications to eliminate minor reactants and
elementary reactions. Through the combination of the above two methods, an efficient
and accurate simplified reaction mechanism was obtained. The simplified
mechanism contains 287 reactions and 44 species. Finally, by using CHEMKIN the calculation software, the
simplified mechanism is used to verify that the ignition delay and laminar
flame speed of methanol and methane are consistent with the experimental data. In order to meet the
simulation requirements of dual fuels, the simplified mechanism needs to satisfy the combustion
characteristics of methanol and methane at the same time. Through a series of
comparisons, it is found that the simulation results of the simplified
mechanism are very similar to the experimental results, which verifies the
feasibility and accuracy of the simplified mechanism.

In conclusion, compared with the
detailed reaction mechanism of GRI mech 3.0 and Galway University, this
simplified mechanism can not only ensure the accuracy and reliability of
simulation results, but also greatly shorten the time required for 3D
simulation. Therefore, this simplified mechanism can be used for
three-dimensional simulation of a methane/methanol dual fuel engine.