Exciplex Method for Remote Probing of Fuel Droplet Temperature

Abstract

Exciplex-based fluorescence thermometry was developed for remote probing of fuel droplet temperature. The liquid fuels tested were n-Heptane, n-Decane and n-Hexadecane which contained 1% Naphthalene and 2.5% Tetramethyl-p-phenylene diamine (TMPD). Also examined was unleaded regular gasoline into which no Naphthalene or TMPD was dissolved. The fuel droplet suspended at the tip of a quartz fiber was allowed to evaporate in a stream of air or gaseous Nitrogen, and its temperature was monitored using a fine thermocouple. The droplet was irradiated with a Nitrogen laser and fluorescence emission spectra were taken by means of a light collection system which consisted of a convex lens, a light stop, a double monochromator and a photomultiplier. The results showed that remote probing of the droplet temperature could be achieved by measuring the ratio of fluorescence emission intensities at two different wavelengths.