Temperature and Density Measurements of Induction Heated Free Jets of Nitrogen and Nitrogen Seeded Argon

摘要

The rotational and vibrational temperatures of nitrogen molecules on the centerline of a low density free jet exhausted through an orifice of 0.5 inch diameter are measured spectroscopically using electron beam excitation. The working gases are pure nitrogen and mixtures of argon and nitrogen. The gas temperatures are elevated by induction heating. The vibrational temperature is frozen from the orifice and the rotational temperature is frozen far downstream from the orifice. Measurements of pure nitrogen free jets imply that the effect of the stagnation conditions on the rotational freezing is described by the parameter PoD/T to the 4/3rd power instead of PoD which is used as a freezing parameter for a free jet at a constant stagnation temperature. The high rotational temperature is determined by comparison between experimental and theoretical distributions of total line intensities of R- and P- branches over the wave length of the first negative system. The rotational temperature of a small percentage of nitrogen molecules in the argon free jet is shown equal to the translational temperature of argon in the higher density region near the orifice. By this devise the seeded argon jet is investigated. Representative Langmuir probe data is discussed. (Author)