A Preliminary Investigation of the Production of Stable Fogs Under Subsaturated Conditions,
CALSPAN ADVANCED TECHNOLOGY CENTER BUFFALO NY
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Under Contract No. N00019-78-C-0349 from the Naval Air Systems Command, Calspan Corporation initiated an experimental investigation of the feasibility of producing stable fogs under conditions of subsaturated relative humidity. The objectives of this limited laboratory investigation were 1 to determine the efficiency of pyrotechnically-generated, hygroscopic aerosols in producing conditions of restricted visibility at both visible and infrared wavelengths at relative humidities 100 and 2 to assess the utility of evaporation retardants in increasing the persistance lifetime of the artificial fogs with lowering relative humidity. In the experiments, measurements of aerosol size spectra 0.01 micron - 10 microns diameters and optical extinction at both visible and infrared wavelengths were obtained as functions of time and changing relative humidity for a variety of aerosol concentration levels. The Salty Dog aerosol fogs were found to be extremely stable, with visibility improvements of only a factor of 2 occuring when relative humidity was reduced 10. The evaporation retardant, cetyl alcohol, was found to be ineffective in reducing the visibility improvement factor.
- Atomic and Molecular Physics and Spectroscopy