Operational gas turbine swirl combustors design map for pure methane and different outlet configurations

Abstract

The most crucial phenomenon limiting gas turbine burner operation is the flashback and blowoff of flame in the combustor during gas turbine operation. In order to avoid this undesirable phenomenon, it is necessary to predict the operational map area of the gas turbine burner. Pure methane has been taken as fuel in this analysis, which attempts to construct a design map with two swirl numbers, 1.2 and 1.5. Different configurations for the outlet of the burner ranged from open flame with a normal nozzle, to cylindrical and conical confinements. The operation map area represents the allowance area of the burner when choosing the equivalence ratio and specified total mass flow rate. The results show that the workable area of the burner increases with the cylindrical and conical confinements, but shows no real difference between the two swirl numbers.

Flame Stability in Swirling and Bluff-Body Burners: A Review

“…It was found that the addition of both cylindrical and conical confinement increased the operating map compared to the open flame, as shown in Figure 9 a. The tangential swirl burner with different nozzle configurations [79,81] An experimental study to examine the impact of exhaust confinement on the stability limits of premixed methane (CH4) and blends of 30%H2 -70%CH4 flames with the same burner shown in Figure 8 but at S = 0.8 was implemented by Abdulsada et al [81] (2012). They reported that the better blowoff limits were with blends of 30% H2 -70% CH4 compared to 100% CH4 as shown in Figure 9 b.…”

“…It can be seen that the presence of confinement in the burner nozzle greatly improves the operating map, and the reason for this improvement is that the presence of confinement maintains the CRZ staying for a longer distance, and helps to stabilization the flame [79]. Additionally, properties of the burner nozzle inner wall can have a significant impact on the flame propagation [83].…”

“…Also, the flashback and blowoff limits (operation map) of a premixed methane flame at two swirl numbers (S = 1.2 and 1.5) has been studied by Abdulsada [79] (2019). A significant improvement was observed in the mixing process of the reactants at the swirl number more than 1.…”

“…In addition, it was noted that in the case of comparison between swirl numbers that are greater than 1 and the difference between them is little, there was no significant difference in the tendency of flashback and blowoff. This is due to the fact that when the swirl number is greater than 1, it gives a good mixing process for the reactants [79].…”

“…In addition to the swirl number's impact, Abdulsada [79] (2019) conducted another experimental study, which is the effect of adding cylindrical and conical confinement to the burner nozzle on the stability map of a premixed methane flame in a swirl burner as shown in Figure 8, at swirl number (S = 1.2). It was found that the addition of both cylindrical and conical confinement increased the operating map compared to the open flame, as shown in Figure 9 a.…”