Experimental and Numerical Study of Chemiluminescence Characteristics in Premixed Counterflow Flames of Methane based Fuel blends

Abstract

Non-intrusive chemiluminescence measurements have been used as heat release rate and equivalence ratio indicators for gas turbine combustor active control. In the present study, measurements and modelling of OH * , CH(A) * , C 2 * , and CO 2 * chemiluminescence are used to examine chemiluminescence sensing of heat release rate and equivalence ratio in premixed counterflow methane -air flames with equivalence ratio from 0.6 to 1.3 and strain rate from 80 to 400 s -1 . Two spectrally resolved detecting optical systems were used to detect spatially-averaged (global) and spatially resolved (local) chemiluminescence characteristics in the reaction zone. A recently published reaction mechanism 1 for the chemiluminescence of the OH * , CH * , and C 2 * species is incorporated to GRI-Mech 3.0. The augmented mechanism is further validated against the experimental results of the present study and is used to predict the chemiluminescence characteristics of premixed counterflow methane -air flames. !(!) = detected signal ! = wavelength H = distance between two opposed jets V 0 = flow bulk velocity at jet exit

Experimental investigation of isothermal and reacting flow characteristics downstream of axisymmetric bluff body stabilizers under stratified or fully premixed inlet mixture conditions

“…After 1970s chemiluminescence received an increased attention for application in combustors, since it is not an intrusive method and it is a very simple, robust and reliable diagnostic system. Many studies have been conducted to connect chemiluminescent species production with the combustion performance, heat release and equivalence ratio and to monitor and control combustor operation [134][135][136][137][138].…”

“…Under this perspective both experimental and computational studies have been performed to provide an effort insight understanding of the chemiluminescence processes and their dependence on various combustion operating conditions [138,139].…”

“…The chemiluminescence sensing of OH*, CH*, C2* and CO2* of hydrocarbon flames has frequently been correlated to various combustion properties, such as equivalence ratio or heat release [134,136,138,206,215]. A variety of experimental and computational studies of chemiluminescence emissions correlations of premixed flames have been performed in recent years, as it seems a well suited and cheap approach for monitoring local, reaction zone equivalence ratios and structural flame properties [138,[216][217][218]. Nevertheless, the overall chemiluminescence spectrum of the flame was not available, as a high sensitivity light spectrometer was mandatory [48], thus, CO2* emission could not be measured.…”