Session: 19-02 Applications

Paper Number: 154188

NOx Reduction Through Swirl Injector for Hydrogen and Methane Combustion in Mild Conditions 

Moderate or Intense Low Oxygen Dilution (MILD) combustion is recognized for its flame stability and ability to achieve reduced peak temperatures under nominal operating conditions. However, during the rapid startup phases of preheated micro gas turbines, particularly with hydrogen as a fuel, there is a heightened risk of combustion instabilities. These instabilities become more pronounced due to hydrogen’s high reactivity, necessitating advanced control measures. In this study, we propose a novel low-swirl injector, specifically designed to mitigate these instabilities. The injector achieves substantial reductions in NOx emissions and enhances combustion stability during both startup and steady-state conditions.

A Partially Stirred Reactor (PaSR) model is employed to evaluate chemical and turbulent timescales, while turbulence-chemistry interactions are accounted for using the Eddy Dissipation Concept (EDC) with a finite-rate chemistry approach, capturing the strong coupling between turbulence and reaction rates. The primary objective of this work is to experimentally validate the MILD combustion model for hydrogen and to numerically assess combustion instabilities under preheated and non-preheated inlet conditions.

Experimental investigations are conducted in a stagnation point reverse flow combustor, where flame dynamics are characterized using advanced optical diagnostics. Following validation with experimental data, numerical simulations are performed to optimize the swirl injector design for hydrogen combustion in a MITIS micro gas turbine. The simulation results demonstrate that the proposed injector design enables stable ignition during rapid startup, while maintaining NOx emissions within single-digit levels under nominal operating conditions.

Presenting Author: Jojomon Joseph MITIS SA

Presenting Author Biography: Dr. Jojomon holds a PhD in Fluid Dynamics from INSA Tolouse. During his PhD, he has conducted applied research at MITIS, Belgium as part of the prestigious Marie Skłodowska-Curie fellowship. With over five years of engineering research experience, he has developed deep expertise in combustion, thermodynamics, and turbulence. His passion lies in creating innovative, sustainable solutions to reduce the environmental impact of energy systems, with a focus on improving the efficiency and sustainability of micro-gas turbines.

Authors:

Jojomon Joseph MITIS SA
Mahdi Jamshidiha Université Libre de Bruxelles, École Polytechnique de Bruxelles, Aero-Thermo-Mechanics Laboratory,
Danish Rehman MITIS SA
Axel Coussement Université Libre de Bruxelles
Alessandro Parente Université Libre de Bruxelles
Michel Delanaye MITIS SA