Functional Group Analysis of Evaporation and Liquid Combustion of Jet-A and Its Surrogate Fuel Based On Quantitative FT-IR Measurements
Published on Jan 4, 2016
· DOI :10.2514/6.2016-0689
This paper reports the evaporation and combustion experiments of small amounts of pool liquid fuel and the preliminary quantification of functional groups including: CH2, CH3, t-butyl, iso-propyl and mono-substituted aromatics using light absorbance in the wave number range of 400-4000 cm -1 . The goal was to develop a method that formulates evaporation characteristics for a complex real fuel and use the results to establish a surrogate’s evaporation rate associated with real fuel’s functional group evaporation rates. Jet-A (POSF-4658) was selected as the real fuel target in this study and a simple mixture of n-decane/iso-octane/toluene was selected to be the surrogate. The experiments included boiling and a pool fire test of 10 mL liquid fuel samples in a Petri dish. The fuel sample liquid mass was recorded before and after each experiment and the liquid fuel samples were collected using a needle at the end of each experiment. The attenueated total reflection (ATR) module of a Fourier Transform infrared (FT-IR) spectrometer was used to facilitate a large number of liquid measurements. The correlation between concentration and transmittance of each functional group was provided by simple mixtures with known compositions. Results show that the evaporation characteristics of Jet-A and the surrogate mixture are extremely different in terms of time evolution of functional group concentrations and total time. Therefore it suggests the evaporation feature of the surrogate mixture itself is less useful to modeling the evaporation of Jet-A. Moreover, the analyses show that the functional group evolutions during evaporation and pool fire experiments of Jet-A were very similar suggesting the functional group consumptions from liquid combustion may be represented by evaporation.