ON THE USE OF LAMBDA PROBES AS OXYGEN SENSORS IN FULL-SCALE FIRE TESTS

摘要

For fire reconstitution and CFD model evaluation, the Police Central Laboratory studies firerngrowth during full-scale tests. Depending on the purpose of these experiments, many parameters arernbe measured, such as temperature, light extinction, radiative heat flux or gas concentration (O2, CO2,rnCO).rnMainly due to the cost of analysers, the laboratory has always been limited in the number of gasrnmeasurement points. It has led to the idea of using lambda probes as oxygen sensors for full-scalernapplications. The adopted solution is based on narrow-band zirconium lambda probes commonly usedrnin the automotive industry for air/fuel mixes optimisation in exhaust systems. In the current state ofrndevelopment, the device is reliable for oxygen concentration ranging from 5 to 21% and presentsrnmany advantages compared to paramagnetic cells. The [0-5%] range of oxygen concentration has notrnbeen investigated yet.rnThe article presents:rn1.the technological choice made for λ-probe application,rn2.the characterization tests of the signal as a O2-Temperature dependent function in the rangern[5-21 % O2] and [20 - 300 ℃],rn3.the first applications during medium-scale tests in partnership with the CORIA of Rouen,rn4.the perspectives for high-resolution oxygen mapping during major full-scale tests and firefightersrntraining programs.rnAmong the problems encountered in the application of such device, it can be mentioned therntemperature-dependent drift or O2 and temperature dependent inertia which are currently studied forrnfurther improvement of the measurement technique. Developed O2-probes are convenient to performrnsimultaneous measurements in many locations of an enclosure in the purpose of comparison ofrnnumerical with experimental data or to provide a better understanding of ventilation issues during firerntests for instance.