Etude de la combustion de gaz de synthèse issus d'un processus de ...

Numerical simulation of a syngas-fuelled engine
6.3 Code validation
Due to the lack of experimental apparatus, model testing has been carried on over
detailed experimental data available in literature and, in particular, the standard CFR,
single cylinder, engine has been chosen for the simulations. Two fuels were selected
that are present on syngas: hydrogen and methane. As far as hydrogen fueling is
concerned, the extensive measurements of Verhelst, (2005) have been chosen as a
reference, while the in-cylinder pressures traces by Bade and Karim, (2001) have been
considered when dealing with methane. An attempt to validate the code by comparison
with experimental results obtained in this work in the RCM is made.
6.3.1 CFR engine
tel-00623090, version 1 - 13 Sep 2011
A Cooperative Fuel Research engine, known as the CFR engine, is an engine originally
used for the determination of fuel octane numbers, now also equipped for gaseous
fuels. It is characterized by its engine speed kept constant by coupled electric motor,
and its variable compression ratio. The main engine specifications are given in Table
6.1.
Table 6.1 - Basic CFR engine data
Items
Specification
Engine type
Cooperative Fuel Research (CFR)
Number of cylinders 1
Bore × Stroke
82.55 × 114.2 (mm)
Connecting rod length
254 mm
Displacement 611.7 cm 3
Compression ratio
Variable
Engine speed
Variable
6.3.1.1 Sub-models
Most of the predictive capability of a quasi-dimensional model relies on the accuracy of
the implemented sub-models. Sub-models are needed for closing the equations for
pressure, temperatures and masses of the two zones: in particular, a combustion submodel
for computing the mass burning rate, and a model of heat transfer through the
walls; a detailed description of them is given in the following for hydrogen-air and
methane-air mixtures.
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