Measurements of submicron fog particles generated in a nozzle

Measurements were made of the size and relative number of particles condensed in a "large" supersonic nozzle. Stagnation temperature was held at 528[delta]R and stagnation pressure was varied from ~ 1/3 to ~ 2/3 atm with the water as the condensing vapor. The mass fraction of water vapor was varied from ~8 x 10-3 to ~30 x 10-3. The size of particles was determined by measurement of light scattered at two angles, making use of the Mie solution for particles above the maximum size for Rayleigh scattering. The size of particles measured was found to be an order of magnitude larger than previously, with radii from ~ 200 to ~ 700 A. It was found that the initial partial pressure of vapor was the best correlating parameter with particle size over the total pressure range, and that the relative number of particles decreased by an order of magnitude as the mass fraction increased. Static pressure measured in the test section of the nozzle showed an increase with initial mass fraction of vapor which was approximately linear.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22158/1/0000589.pd