Large-Eddy Simulation of Turbulent Combustion in Multi Combustors for L30A Gas Turbine Engine

Abstract

When designing a combustor, numerical analysis should be used to effectively predict different performances, such as flame temperature, emission, and combustion stability. However, even with the use of numerical analysis, several problems cannot be solved by investigating single combustors because, in an actual engine, interactions occur between multiple combustors. Therefore, to evaluate the detailed phenomenon in an actual combustor, the interactions between all combustors should be considered in any numerical analysis. On the other hand, a huge amount of computational cost is required for this type of analysis. Here a large-eddy simulation employing a flamelet/progress variable approach is applied to the numerical analysis of industrial combustors. The combustor used for this study is the L30A from Kawasaki Heavy Industries, Ltd. Computations are conducted with a supercomputer (referred to as the “K-computer”) in the RIKEN Advanced Institute for Computational Science. All combustors in the L30A engine (from the compressor outlet to the turbine inlet) are simulated, including the fuel manifold. This engine has eight can combustors that are connected through the fuel manifold and compressed air housing unit. The total number of elements is approximately 140 million. The flow patterns for each combustor are similar in all cans. A swirling flow from the main burner is formed and accelerated by the supplemental burner. There is a high-temperature region before the supplemental burner. The flow field and temperature distribution in an actual combustor interacting with other combustor cans are simulated adequately. The mass flow rate of the air and those of the fuels are distributed equally for each can. Therefore, the outlet temperature difference for each can is also very small.

Prediction of CO emissions in turbulent super lean premixed combustion under pressurized conditions using an LES/non-adiabatic FGM approach

“…Therefore, we apply the NA-FGM approach [14] to include the effect of heat loss. The flamelet library, using the effect of the considered heat loss [16], is calculated using equations ( 6), (7) and (9).…”

“…In particular, a large-eddy simulation (LES), which models an eddy smaller than the cell size, has gained increasing application in recent years, because the application of an LES to complex reacting flows has been realistic with advancements in the supercomputing performance [e.g. [2][3][4][5][6][7][8]. As the turbulent combustion model, the flamelet approach [9], which utilizes the flame characteristics in the database (i.e., the flamelet library), is effective in terms of computational costs and is widely used instead of directly solving the Arrhenius equations when considering the detailed chemical reaction mechanisms.…”

Numerical Simulation of CO Concentration on Flame Propagation in the Vicinity of the Wall -Validity of Non-Adiabatic FGM Approach-

“…Computational fluid dynamics (CFD) is a powerful tool to investigate the detailed distributions of various chemical species and temperature under the complicated combustion fields. CFD has been used to support to engineers in predicting the property of flame dynamics during the combustor design process [3][4][5][6][7][8][9]. Prediction of CO emission with high accuracies is required consideration of the detailed reaction mechanism in general.…”