A relatively simple experimental technique is used for making measurements of relative deposition rates from flowing combustion gases containing condensible inorganic vapors(here sodium sulfates).
In using this "flash evaporation" technique, one first accumulates an inventory of condensate on a Pt-ribbon target maintained below the dewpoint and then flash-evaporates this inventory into the filament wakes, where its sodium content is monitored by sodium-atom emission spectoroscopy.
As implemented here, this method is shown to have a number of important advantages over more time-consuming alternatives(e.g. gravimetric) or demanding alternatives(e.g. optical reflectance interferometry or ellipsometry).
Illustrative $Na_2SO_4$-deposition rate data has been obtained in a series of alkali-seeded propane/air atmospheric pressure flat flames as a function of wall temperature and feeding rate.
This class of experimental methods appears to be well-suited to the study of multiphase deposition when wall temperature is cooled below the dew point for inorganic vapors.
