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

Experimental set ups and diagnostics
The ignition coil used is a traditional automobile spark coil (Siemens S10203000A),
supplied by a 12 V battery, in which the load could be supplied by an electrical signal or
optical command. In this work an electrical signal command was used with a load time
of 5 ms.
The procedure to use this chamber for any combustion experiment is:
- Combustion chamber at vacuum. The vacuum was considered in this work to
be 12 mbar or less;
- Mixture preparation within the chamber;
- Central ignition of the mixture by a spark;
- Burned gases exhaustion;
- Maximum initial pressure of 3.0 bar.
tel-00623090, version 1 - 13 Sep 2011
3.1.3 Spherical chamber
The spherical combustion chamber shown schematically in figure 3.2 is composed by
three main parts. Two of which, are the spherical calottes and the third, supports the
different devices such as the fast response pressure sensor, ignition electrodes and
ionization probes. The inside sphere cavity is lodged in a stainless steel cylindrical
block.
Ǿ 160 mm
Electrode
Figure 3.2– Spherical combustion chamber
Two typical automobile electrodes with 0.6 mm diameter are symmetrically introduced
at the center of the sphere. The electrodes are feed by the coils at 12 Volts.
An electronic device developed by Fisson et al., (1994) is used to protect the ignition
circuit from the measurement system. When current crosses the secondary circuit of
the ignition coil, one diode in series generates an optic signal and a phototransistor
creates a proportional voltage to the current. This signal is the command to the
pressure signal to be recorded.
The pressure is measured during combustion through a piezo-electric pressure
transducer KISTLER 601A. This sensor is connected to an amplifier Kistler 5011
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