Optical diagnostics of pentane autoignition using corrected filtered natural emission of species (C-FNES) technique

Abstract

A recently developed optical technique, based on filtered infrared emission of species, was used to measure gas temperature, carbon monoxide, and carbon dioxide concentrations during n-pentane mixture's autoignition. The optical technique is named Corrected Filtered Natural Emission of Species (C-FNES) and is based on the plane of line-of-sight radiation emission of species in the mid-wavelength range. Thus, the whole combustion chamber can be observed and analyzed to determine gas temperature and species concentrations. The main objective of this work is to evaluate and validate C-FNES technique in comparison to the laser absorption spectroscopy (LAS) technique. In addition, the technique was used to evaluate the kinetic model performance in predicting gas temperature and some of the species concentrations. Simulation was performed using the LLNL and NUI Galway mechanism models and which demonstrated their inability to predict the FNES and LAS measured data. It was shown that the corrected FNES technique produces similar data as that obtained through the LAS technique under the studied conditions, and can be used to measure the gas temperature and species concentration at a wide range of temperatures.