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

Numerical simulation of a syngas-fuelled engine
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1000
Volume (cm3)
800
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Experimental
Polynomial
0
180 210 240 270 300 330 360 390 420 450 480 510 540
Crank Angle (degrees)
tel-00623090, version 1 - 13 Sep 2011
Figure 6.7 – In-cylinder volume polynomial fitting: compression and expansion of downdraft
syngas with ignition 12.5 ms BTDC.
For this reason, the volume fitting function was divided into two parts one for
compression and another for expansion reducing the fitting error to 0.5%.
6.2.2.3 Heat transfer
A common practice in engine testing for combustion diagnostic is, prior to the usual
firing tests, to test the engine in motored conditions, with air as the only working gas,
and the in-cylinder pressure being recorded by a piezoelectric transducer (Lapuerta et
al., 2003). The study of the compression process in a RCM operating without
combustion is useful to identify different parameters related with its operation, namely
the heat transfer to the walls. Once determined, these parameters can also be used
during the usual firing cycle. In fact, a determinant parameter in the code is the heat
transfer coefficient, which should be calibrated. The pressure signals of single
compression are used to determine the heat transfer on the RCM. Figure 6.8 shows
the comparison between experimental and numerical in-cylinder pressure without
combustion.
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