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

Abstract

The combustion, exhaust-gas concentrations, and stability characteristics of premixed CO 2 -diluted oxy-propane (C 3 H 8 /O 2 /CO 2 ) flames were investigated computationally using large eddy simulations (LES) in a swirl-stabilized model gas-turbine combustor. The simulations were carried out for ranges of equivalence ratio (Φ: 0.26-0.80) and oxygen fraction (OF: 35%-60%) at a fixed bulk inlet velocity of 5.2 m/s. The results indicate that the reaction rates increase with the increase of Φ and OF. Flames of the same adiabatic flame temperature (T ad ) show similar macro-and flowfield-structures, in terms of flame shape, flow circulation, and temperature, and species distributions, irrespective of the values of Φ and OF. At higher T ad , the flames were observed to be more compact with reduced flame thickness and higher Damkohler number (Da). In all cases, Da > 1 were observed, indicating the dominance of reaction rate in oxy-propane flames than the diffusion rate. A secondary IRZ was also observed near the outlet of the combustor. Mixture composition and combustion temperature influence the CO concentration at the combustor exit. The highest CO emission was observed at 0.17 ppm for the flame with highest Φ and T ad , meanwhile no CO emission was seen for flames with high OF and low Φ among the studied cases. Highlights 1. Adiabatic flame temperature is a quantifying parameter for flame

Analysis of Highly CO2-Diluted Oxy-propane Flames Stabilized over a Multihole Burner of a Model Gas Turbine Combustor

“…Figure 9 shows the velocity streamlines mapped over the temperature contour at the centerline plane of the combustor in Ø = 0.313, OF = 60%, T ad = 1900 K. Unlike the swirl-stabilized C 3 H 8 /O 2 /CO 2 flames, examined in the earlier study by Nemitallah et al, 37 where the flames are characterized by two recirculation zones, the inner recirculation zone (IRZ) and outer recirculation zone (ORZ), the flow-field in the multihole combustor can be characterized by the presence of the ORZ only. Here, the IRZ (or central recirculation zone) is the recirculation at the combustor center induced by the swirl effect that broadens the blowoff limit through reutilizing the active chemical species and heat to the flame root in the exit of the combustor.…”

“…Thus, to maintain an identical power density (8.36 MW/m 3 /bar) among the combustors, the mass fluxes are fixed, ensuring identical fuel mass flowrate supply to the combustor. A detailed description of the experimental setup and CFD model for the compared swirl-stabilized combustor are presented in the authors’ earlier studies. , …”

“…A detailed description of the experimental setup and CFD model for the compared swirl-stabilized combustor are presented in the authors’ earlier studies. 22 , 37 …”

Analysis of methane, propane, and syngas oxy‐flames in a fuel‐flex gas turbine combustor for carbon capture

“…However, the formation and recirculation in ORZ is case sensitive for a fixed combustor design and is also a vital parameter for the flame stability. The effects of ORZ in various OF and Φ have been examined in details in earlier experimental 29,31,73 and numerical 32,66,67 studies for individual fuels.…”

“…The details of the validation process can be obtained from authors previous works. 63 In addition, the model is contrasted with the experimental results on the same combustor on H 2 -enriched oxymethane combustion 65,66 and oxy-propane combustion 67 as well. These earlier experimental works focused on the combustion characteristics in a model combustor, designed to have identical PD (i.e., heat input per combustor volume and pressure, unit: MW.m À3 .bar À1 ) to actual GT combustor.…”