Measurements of the initial density distribution of gas puff liners by using rayleigh scattering

Various optical techniques are available to measure distributions of the gas concentration in supersonic jet. The interferometry using two-dimensional interferograms seems to be the most informative one. Unfortunately, this method provides only the density values that are averaged along the probing beam. In the case of axially symmetrical jets one can determine the distribution of gas concentration after routine mathematical treatment of interferograms (solution of Abel equation). This treatment produces a tolerable error only in the case of the monotonic distribution of the density, i.e. without any inner spaces. Finally, the sensitivity of the two-dimensional image interferometer is very often not sufficient to investigate jets with low concentrations of particles. Objects of this kind require using of photoelectric interferometers. But great increase of sensitivity involves a rather complicated devices.