Session: 04-16 Hydrogen Emissions I

Submission Number: 175427

Predictive Modeling of NOx Emissions in Lean Micro Mixer Combustors With Natural Gas-Hydrogen Blends 

Dry Low NO_x micromixer combustors are a key technology for reducing emissions in gas turbines operating with hydrogen-enriched fuels. However, under lean premixed conditions, the flame exhibits complex behavior -including high flame speeds, strong differential diffusion and sensitivity to flame stretch and extinction. These challenges are amplified at high pressures and low equivalence ratios, where hydrogen’s chemical kinetics significantly diverge from those of conventional hydrocarbon fuels. Accurate NOx prediction under these conditions remains difficult due to the limited validity of widely used chemistry-pathways, which often fail to capture the combined effects of hydrogen reactivity, pressure sensitivity and lean-burn chemistry. Turbulence also plays an important role in modifying the flame dynamics that govern NOx formation in premixed micromixer combustors. In this work we apply the Thickened Flame Model (TFM) as a surrogate Turbulence Chemistry Interaction (TCI) model for NOx evaluation. The model is coupled with a reduced chemical mechanism, specifically adapted to account for hydrogen’s high reactivity and pressure sensitive NOx-pathways. High fidelity Large Eddy Simulations (LES) are conducted on a scaled lean premixed micromixer combustor, operated with various hydrogen-methane mixture blends at E/F-class cycle conditions. Simulated results are compared against data from an experimental combustor test rig. The model shows good agreement in capturing the flame structure, temperature and NOx trends. The findings underscore the importance of integrating blend-specific chemical kinetics with TCI-aware modeling approaches such as TFM for reliable NOx prediction in hydrogen rich combustion systems.

Presenting Author: Samir Rida GE Vernova

Presenting Author Biography: Samir manages the advanced combustion modeling, simulation and methods team at GE Vernova. He has more than 25 years of experience in gas turbine combustion modeling and design. He holds a Ph.D. in mechanical engineering from Polytechnique Montreal.

Authors:

Samir Rida GE Vernova
Michael Hughes GE Vernova
Hasan Karim GE Vernova
Wessam Estefanos GE Vernova
Carlo Arguinzoni Ansys part of Synopsys
Stefano Orsino Ansys part of Synopsys
Adam Norman Ansys part of Synopsys
Karthik Puduppakkam Ansys part of Synopsys
Naseem Ansari Ansys part of Synopsys
Mohammadreza Farokhi Ansys Canada Ltd. a part of Synopsys