Laminar flame structure in a low-pressure premixed H$_2$/O$_2$/Ar mixture

The chemical structure of a stoichiometric hydrogen-oxygen flame stabilized on a flat burner at a pressure of 47 torr is studied by molecular-beam mass spectrometry and computer simulation. Concentration profiles are measured for the stable flame components Н$_2$, O$_2$, and Н$_2$О, as well as for the atoms and radicals H, O, and OH. The concentration profiles calculated using two different kinetic mechanisms are in acceptable agreement with experimental data. It is also shown that for sampling probes with thin walls ($<$ 0.1 mm) at their tips, there is no need to perform the calculations using a specified temperature profile measured by thermocouples located near the aperture of the sampler, as recommended by a number of authors.