Session: 04-24 Combustion - Modeling II

Submission Number: 177660

Large-Eddy Simulation Study of Flame Flashback in a Multi-Tube Micromix Gas Turbine Combustor at High-Pressure Conditions 

Micromix combustion is a promising technology for stationary gas turbines that aims to deliver high-efficiency, ultra-low-NO_x combustion with a greatly reduced risk of autoignition. Flame flashback is, however, one of the key challenges towards enabling lean premixed gas turbines with fuel flexibility. An accurate prediction of fuel and flow conditions marking the onset of flashback is of key importance to industrial gas turbine engineers. To this end, a first-of-their-kind high-fidelity large-eddy simulations (LES) are performed to numerically investigate the flow and combustion characteristics pertaining to flame flashback phenomena for high-hydrogen blends in a full-scale multi-tube micromix gas turbine combustor at practical high-pressure operating conditions. The LES framework incorporates finite-rate chemistry with detailed chemical kinetics and differential diffusion. In addition, adaptive mesh refinement (AMR) is leveraged to achieve a good trade-off between predictive accuracy and computational cost. Non-reacting as well as reacting flow simulations are performed for examples of both hydrogen-natural gas blend (96.5% hydrogen by volume) exhibiting no flashback and 100% hydrogen exhibiting flashback. A skeletal mechanism for hydrogen-natural gas blends is developed and employed to reduce the computational cost of LES for the 96.5% hydrogen blend. The LES model is validated against available experimental data for flashback occurrence and combustor exit temperature. Flow features within the Micro Mixer tubes and the resulting fuel-air mixing characteristics are first analyzed using the cold flow LES results. Subsequently, the reacting flow LES results are investigated to understand the physico-chemical mechanisms driving flame stabilization and occurrence of flashback for 100% hydrogen. Further, it is shown that the occurrence of flashback leads to redistribution of flow velocity, inlet backpressure, mass flow rates, and fuel-air mixing across the Micro Mixer tubes due to coupled flame-flow interactions.

Presenting Author: Pinaki Pal Argonne National Laboratory

Presenting Author Biography: Dr. Pinaki Pal is a Principal Research Scientist in the Advanced Propulsion and Power Department within Argonne’s Transportation and Power Systems (TAPS) division. His research interests broadly lie in the areas of computational fluid dynamics (CFD), turbulent multiphase combustion modeling, turbulent boundary layer flows, heat transfer, scientific machine learning (SciML), uncertainty quantification (UQ), multi-fidelity surrogate modeling, high-order numerical methods, high performance computing (HPC), alternative fuels (hydrogen, ammonia, biofuels), and extreme/rare combustion events with relevance to a wide range of applications pertaining to design and optimization of propulsion/power systems (gas turbine engines, rotating detonation engines, piston engines) and manufacturing processes.

Authors:

Pinaki Pal Argonne National Laboratory
Shubhangi Bansude Argonne National Laboratory
Islam Kabil Argonne National Laboratory
Samir Rida GE Vernova
Dwayne Debruhl GE Vernova
Hasan Karim GE Vernova