Effects of adiabatic flame temperature on flames' characteristics in a gas-turbine combustor

In this study a comparison between the premixed methane oxygen-enriched-air (CH4/O-2/N-2) and oxymethane (CH4/O-2/CO2) in a gas-turbine model combustor that imitates pre-mixers in operational air fuel dry low emissions gas turbines is presented. The comparison and analyses that follow in this study are based on the results of experiments conducted. The combustion stability maps were obtained through the estimation of acoustic limits and measurement of blowout limits within the space of equivalence ratio (phi) - oxygen fraction (OF). The stability maps obtained were superimposed on the contour plots of constant adiabatic temperature (T-ad), Reynolds number (Re), and power density (PD) of the combustor. Effects of T-ad on flame macrostructure, flame stability, flame speed, and blowout mechanism were investigated. The temperature distributions were also measured. The study results indicated that blowout of CO2 as well as N-2 flames occur at constant T-ad. These results are more pronounced in the case of the multi-hole burner because, such burner is not characterized with sporadic nature of flame lifting and reattachment that dominate the occurrence of a blowout in swirl burner; for a given OF, phi & nbsp; at which CO2 flames blowout is higher than that of N-2 flames due to the poorer resistance of oxy-flames to blowout as compared to air flames; the stable combustion zone of CO2 flames is larger than that of N-2 flames. (C)& nbsp;2022 Elsevier Ltd. All rights reserved.

Automated summary

This study compares the combustion characteristics of premixed methane oxygen-enriched air and oxymethane in a gas-turbine model combustor. The results show that both CO2 and N-2 flames experience blowout at constant adiabatic temperature, with CO2 flames having a higher blowout OF value. The stable combustion zone of CO2 flames is larger than that of N-2 flames.