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arXiv · 0706.4011

Determination of density and concentration from fluorescent images of a gas flow

Marco Belan·Sergio De Ponte·Daniela Tordella
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Abstract

A fluorescent image analysis procedure to determine the distribution of species concentration and density in a gas flow is proposed. The fluorescent emission is due to the excitation of atoms/molecules of a gas that is intercepted by an electron blade. The intensity of the fluorescent light is proportional to the local number density of the gas. When the gas flow is a mixture of different species, this proportionality can be exploited to extract the contribution associated to the species from the spectral superposition acquired by a digital camera. This yields a method that simultaneously reveals species concentrations and mass density of the mixture. The procedure is applied to two under-expanded sonic jets discharged into a different gas ambient - Helium into Argon and Argon into Helium - to measure the concentration and density distribution along the jet axis and across it. A comparison with experimental and numerical results obtained by other authors when observing under-expanded jets at different Mach numbers is made with the density distribution along the axis of the jet. This density distribution appears to be self-similar.

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Marco Belan, Sergio De Ponte, Daniela Tordella. 2007-07-03. Determination of density and concentration from fluorescent images of a gas flow. https://doi.org/10.1007/s00348-008-0493-5

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