Characteristics of Oxyfuel Combustion in Lean-Premixed Multihole Burners

Abstract

This paper presents the results of an experimental investigation of combustion characteristics of nonswirl CH4/CO2/O2 flames under atmospheric pressure in a lean-premixed multihole burner’s gas-turbine model combustor. The CO2 and O2 are well premixed and then channeled to a test rig, which is made up of a 2 in. diameter 1 m long pipe to premix the fuel and oxidizers before getting to the multihole burner. The burner consists of main holes and subholes that prevent flashbacks that may lead to rig explosion. The burner imparts jet to the premixed measured composition of CH4/CO2/O2. The results indicated that the adiabatic flame temperature (T ad) is a strong controlling parameter in quantifying the stability map and combustor flame shape; variation in oxygen fraction and equivalence ratio influence the flame shape, whereas the equivalence ratio (ϕ) is the major controlling parameter of temperature distribution within the combustor. The results also indicated that the stability map does not follow the lines of constant power density, mass flow rate of the mixture (ṁ mix), and Reynolds number (Re).

Numerical analysis supported with experimental measurements of premixed oxy‐propane flames in a fuel‐flex gas turbine combustor

“…At same T ad , the C 3 H 8 /O 2 /CO 2 flames were found experimentally to have similar shapes with similar temperature profile near the flame core. This effect of T ad F I G U R E 2 Combustor mesh adopted in the developed numerical model [Colour figure can be viewed at wileyonlinelibrary.com] on flame macrostructure and combustor stability was observed in previous experiments on oxy-methane combustion in a swirl-stabilized burner 19,[52][53][54] and also in micromixer (MM) burner. 53,55 A set of pints within the stable combustion region was selected to present the change in flame shapes in different OF, ϕ, and T ad .…”

“…This effect of T ad F I G U R E 2 Combustor mesh adopted in the developed numerical model [Colour figure can be viewed at wileyonlinelibrary.com] on flame macrostructure and combustor stability was observed in previous experiments on oxy-methane combustion in a swirl-stabilized burner 19,[52][53][54] and also in micromixer (MM) burner. 53,55 A set of pints within the stable combustion region was selected to present the change in flame shapes in different OF, ϕ, and T ad . Figure 5 depicts the side-view images of the flames at fixed OF of 60% (A-E), fixed ϕ of 0.5 (F-J), and fixed T ad of 2302 K (K-P).…”

“…48 Similar conclusions were reported in previous studies. 19,37,48,[52][53][54] Despite being of different Φ, the flame lengths of these two cases are alike because of the different OF values for the two flames to have the same Here, the flame in case 6 is short and strong, the flame in case 7 is relatively weaker and taller, and the flame in case 8 is the tallest and weakest among these three flames. Since reactivity is enhanced in oxygen-rich environments with the accelerated combustion chemistry and, consequently, improved flame speed (see Figure 7), the flame becomes weaker when going from case 6 to case 8 due to the scarcity of oxygen within the combustor.…”

Review of Fuel/Oxidizer-Flexible Combustion in Gas Turbines

“…Badra et al 92 have proposed a combustor design based on the MM concept but for nonpremixed flames, which can preheat the fuel and oxidizer using the heat from the combustion products. Aliyu et al 93 have performed one of the first studies of oxy-fuel combustion using a MM-like burner. They have reported that the main parameter controlling flame stability and structure is the adiabatic flame temperature (T ad ), as observed in Figure 17.…”

“…Figure 17. Stability map of a MM-like oxy-fuel combustor operating at fixed jet velocity, plotted against the contours of a constant adiabatic flame temperature 93. …”