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Show - b- Three types of measurement were performed : * temperature using a fine-wire thermocouple, * velocity using Laser Doppler Anenometry (LOA), * concentrations of stable chemical species (CH4, C02, CO, 02, NOx). 4.1.2 Description of the test device To provide access to the heat chamber for measurement probes, Gaz de France defined and had built a section of a furnace suitable for the test cell described in section 2.2. The model has a cylindrical inner section (dia. 900 mm), a total length of 1.3 m and a continuous horizontal slit of 0.9 m for measurements along the horizontal plane through the axis of the burner. It also has a dynamic sealing system so that the probe can be moved along the slit without changing the operating conditions of the burner. 4. 1.3 Description of measurement techniques This section provides a brief description of the three measurement techniques used: * temperature measurement The high temperature levels to be measured required the use of an iridiumliridium-rhodium 40% thermocouple with a diameter of BOJ,lm: this material has a higher melting temperature than the type B thermocouple habitually used and far greater mechanical resistance. When a fine-wire thermocouple is used for temperature measurement, it is possible to monitor the temperature fluctuations of the fluid up to approximately 1,000 Hz using appropriate numerical signal post-processing [4]. * Velocity measurement The LOA measurement implemented is a semi-intrusive technique (opticalfibre probe inserted into a cool probe), which serves to determine the two instantaneous velocity components (axial and tangential) along the z-axis (burner axis) and y-axis (vertical axis). We then deduce the velocity mean and RMS along the two axes. For this purpose, the combustion air was seeded with zircon particles [5]. * Measurement of chemical specifies concentrations The mean concentrations measurement of stable chemical species (CH4, C02, CO, 02, NOx) in reactive flows requires quenching of the sample. At the inlet of the probe, the chemical reactions are frozen by a thermal (by cooling the probe extremity) and aerodynamic (by a sonic nozzle) quenching. Then the sample is transported to a set of analysers. . . .1 .. |