Fuel effects on lean blow-out in a realistic gas turbine combustor

Towards the implementation of alternative jet fuels in aviation gas turbines, testing in combustor rigs and engines is required to evaluate the fuel performance on combustion stability, relight, and lean blow-out (LBO) characteristics. The objective of this work is to evaluate the effect of different fuel candidates on the operability of gas turbines by comparing a conventional petroleum-based fuel with two other alternative fuel candidates. A comparative study of fuel properties is first conducted to identify physico-chemical processes that are affected by these fuels. Subsequently, large-eddy simulations (LES) are performed to examine the performance of these fuels on the stable condition close to blow-out in a referee gas turbine combustor. LES results are compared to available experimental data to assess their capabilities in reproducing observed fuel effects. It is shown that the simulations correctly predict the spray main characteristics as well as the flame position. The change in OH*-emissions for different fuel candidates is also qualitatively captured. An analysis of the flame anchoring mechanisms highlights the fuel effects on the flame position. Finally, the LBO-behavior is examined in order to evaluate the LBO-limit in terms of equivalence ratio and identify fuel effects on the blow-out behavior.