Influence of surface roughness on burner characteristics and combustion performance of AM combustors

Psomoglou, Ianos 2023. Influence of surface roughness on burner characteristics and combustion performance of AM combustors. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

The transformation of the fossil fuel-based energy sector to a resilient, secure, and environmentally friendly equivalent, could potentially be achieved through the utilisation of “green” hydrogen-based energy. Although the introduction of pure, or blended hydrogen fuels to the power generation sector is associated with serious operability issues, novel manufacturing methods including Additive Manufacturing (AM) could assist in addressing such issues and facilitate the transformation of the power generation industry. Apart from the environmental, operational, and economic benefits afforded through AM, the latter is capable of delivering “manufacturable” surface roughness, enhancing the production efficiency of components and potentially improving gas turbine performance. This thesis aims to gain an understanding, through CFD and empirical investigations, of the impact of surface roughness on aerodynamics, combustion performance and emissions of a generic AM combustor characteristic of practical burners utilising conventional methane, pure hydrogen and an energy balanced mixture of methane and hydrogen. Parametric combustion studies of the selected fuel types are conducted in a new generic swirl burner under atmospheric pressure and elevated temperature conditions, relevant to practical burner designs. A system comprising of several diagnostic tools has been developed and operated to accommodate the empirical investigation of surface roughness and deliver the relevant research objectives. Additionally, a computational study of the impact of surface roughness on the resultant aerodynamic flow field has also been designed and implemented. The effectiveness of the employed computational method was supported by the experimental results. The analysis of the empirical and computational findings of the present thesis, aims to build upon the existing knowledge concerning the influence of surface roughness on burner characteristics and combustion phenomena, informing gas turbine manufacturers on potential advantages and economic incentives of AM burners. With increasing surface roughness, the flame location is shifted towards the centreline of the burner, due to the alteration of the aerodynamic flow field. This observation is further supported computationally. The trend is consistent under any fuel type studied and did not influence the NOx emissions or the burner stability envelopes.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Engineering
Uncontrolled Keywords:	1) Additive Manufacturing (AM) – 3D printing 2) Surface roughness 3) Gas turbine (GT) 4) Swirl-stabilised premixed combustion 5) Hydrogen (H2)/Methane (CH4) 6) Computational Fluid Dynamics (CFD)
Date of First Compliant Deposit:	11 October 2023
Last Modified:	12 Oct 2023 08:13
URI:	https://orca.cardiff.ac.uk/id/eprint/162894

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