Droplet lasing spectroscopy applied to droplet stream flames

Droplet lasing spectroscopy (DLS) has been applied to the measurement of dr oplet size and vaporization rates in both reacting and non-reacting rectili near droplet streams. A Berglund-Liu droplet generator was used to generate a stream of droplets, approximately 63 microns in diameter and 6.5 droplet diameters apart. Ethanol, methanol, and a pentane/ethanol mixture were dop ed with Rhodamine 6G. Lasing spectra were examined in the steady-state comb ustion regime. In the pentane/ethanol case the measurements were carried ou t in a sooting region of the flame. In some cases, vaporization rates were high enough to measure the rate from consecutive droplets, yielding a quasi -instantaneous measurement. In all cases, the D-2 law of droplet vaporizati on was evident. In addition, photographs of the flames yielded measurements of flame height and thickness. (C) 1999 by The Combustion Institute.