Enhancement of wet ammonia combustion with fuel cracking strategy

Combustion is the cornerstone for generating energy in various sectors and applications. The ever-increasing demand for decarbonisation of combustion technologies in order to reduce or eliminate undesirable emissions has created a major challenge, putting tremendous pressure on the international research community to develop alternative fuels.

Ammonia has recently been explored as a promising carbon-free fuel and a great alternative to hydrocarbon fuels to achieve zero-carbon emissions. Conventional methods for enhancing ammonia combustion have the potential to improve the combustion drawbacks of ammonia and reduce NOx emissions to some extent. However, blending ammonia with hydrocarbon fuels will not avoid carbon emissions.

Therefore, it is a requirement to have an instantaneous ammonia combustion approach for practical and industrial applications, Ammonia/Hydrogen/Nitrogen/Water combustion is one of the most promising solutions to enhance the combustion performance of ammonia and to reduce NOx emission.

The present PhD research aims to enhance ammonia combustion numerically and experimentally to reach ultra-lean ammonia combustion coupled with near zero NOx emissions for industrial applications.

We are facing a challenge with the computational power and time as we are working on a 3D dump combustor with an annular axial swirler resulting in a turbulent and unsteady flow structure. Also, a detailed chemical kinetics is used which has a high complexity in the sequence of reactions for ammonia consumption and product formation. Additionally, a 0D ammonia kinetics code. Therefore, the model is very complex and need a high computational power to get a high accuracy result.

Our current research endeavours are centred around the meticulous execution of a mesh independence test and the rigorous validation of an established experimental benchmark within the realm of swirl-stabilized combustors. This phase of our investigation marks the culmination of foundational activities, positioning us at the threshold of advancing towards the exploration of diverse blending and cracking ratios. The primary focus of this subsequent phase lies in the nuanced examination of flame structure and emissions characteristics.

The mesh independence test serves as a critical precursor, ensuring the robustness and reliability of our computational simulations. By systematically varying the mesh resolution, we aim to discern the optimal level of discretization that guarantees convergence and accuracy in our numerical results. This empirical foundation is indispensable for the forthcoming stages of our study.

Simultaneously, the ongoing validation against an existing experimental benchmark is an essential aspect of our research framework. This facet not only underscores the credibility of our computational model but also substantiates the fidelity of our numerical simulations in capturing the intricacies of real-world combustion phenomena within swirl-stabilized combustors.

Upon the successful completion of these preliminary phases, our research trajectory will pivot towards the introduction of diverse blending and cracking ratios. This strategic evolution aims to unravel the multifaceted dynamics of combustion, particularly elucidating the influence of fuel composition on flame structure and emissions characteristics. The application of distinct ratios will facilitate a comprehensive understanding of the interplay between ammonia blending and hydrogen cracking within the combustor environment.

The scientific significance of this study lies not only in the refinement of our computational model but also in its potential to contribute valuable insights to the broader scientific community. We anticipate that our findings will enrich the discourse surrounding combustion dynamics in swirl-stabilized combustors, fostering advancements in both fundamental understanding and practical applications.

For more information about the project contact Dr Manosh Paul (Manosh.Paul@glasgow.ac.uk), Professor of Thermofluids at James Watt School of Engineering at the University of Glasgow.

For a list of the research areas in which ARCHIE-WeSt users are active please click here.