Les-Based Investigation of The Thickened Flame Model In A Jet-Stabilized Hydrogen-Fuelled Micro Gas Turbine Burner

Abstract

Hydrogen has gained increasing attention as an energy carrier due to the growing demand for reliable, efficient, and demand-oriented energy and heat supply. In this framework, decentralized Combined Heat and Power (CHP) systems are particularly attractive because of their high overall efficiency and their compatibility with locally produced hydrogen. Among the available technologies, micro Gas Turbines (mGTs) represent a promising solution thanks to their high load flexibility, fuel versatility, and low maintenance requirements. However, the use of 100% hydrogen in mGT combustors remains challenging, mainly because of the high inlet temperatures associated with exhaust gas heat recovery. Combined with hydrogen's wide flammability range and low ignition energy, these conditions may increase the risk of flashback, auto-ignition, and thermal loads that could affect burner stability and structural integrity. This study investigates the mGT F400S.3 combustor developed by the German Aerospace Center (DLR), which enables 100% hydrogen operation through a jet-stabilized combustion concept. A high-fidelity Large Eddy Simulation (LES) approach is applied to analyze the burner first under atmospheric conditions and then under pressurized conditions representative of real mGT operation. Turbulence-chemistry interaction is modeled using an extended Thickened Flame (TF) formulation. The atmospheric LES results are validated against experimental OH*-chemiluminescence measurements, showing good agreement in terms of flame shape and lift-off height. The validated numerical setup is then extended to pressurized operation, demonstrating stable hydrogen combustion without flashback or auto-ignition and providing insight into flame stabilization mechanisms under realistic mGT conditions.