Heat Release Rate from a Two-Phase Kerosene/Air Flame Using Chemiluminescence

An experimental method based on chemiluminescent measurements is developed to determine the heat release rate produced by a two-phase flow kerosene/air flame. This quantity is known to be proportional to the air mass flow rate and the equivalence ratio. Experimental studies are carried out downstream of a liquid fuel injector used in aeronautical combustion chambers. The chemiluminescent spectra of the flame are analyzed for different air mass flow rates and equivalence ratios ranging from 0.4 to 0.71 in the steady-state flame configuration. The broadband background emission due to CO2* emission (where * indicates an electronically excited specie) and soot radiation is first evaluated. Then, the analysis of the chemiluminescent emission from OH*,CH*, C2*, and CO2* indicates that the OH*/CH* and OH*/CO2* ratios may be used to determine both the instantaneous equivalence ratio and the air mass flow rate. An example of the application of this method to measure fluctuations in the heat release rate induced by acoustic excitation of the flame is shown.