Impact of the Primary Zone Excess Air Ratio in Gas Turbine Engine Combustors on Pollutant Emissions

Abay Mukhamediyarovich Dostiyarov, Iliya Krastev Iliev, Yerdaulet Baigozha, M B Kumargazina, Nurasyl Tolembay, Hristo Ivanov Beloev, Ivan Hristov Beloev

2026

Full text Open access: Gold Metadata (CSL-JSON)

DOI 10.3390/engproc2026154053

Data confidence 85 high

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Abstract

The transition to a low-carbon energy paradigm requires reducing nitrogen oxide NOx and carbon monoxide CO emissions to 5–9 ppm. This study investigates the impact of the primary zone excess air ratio α and mixing quality on pollutant yields, addressing the “seesaw” trade-off mechanism between NOx and products of incomplete combustion. Analysis of Lean Premixed and Micromix technologies demonstrates that achieving NOx levels below 5 ppm requires local α fluctuations to remain within a root-mean-square deviation of 3–4%. An original burner design with an intelligent emission control system is presented, enabling dynamic adjustment of local αin to maintain combustion within a narrow stability window. Experimental results confirm that minimum toxicity, with NOx concentrations below 20 ppm, is achieved at αin = 1.7–1.8. The implementation of this technology ensures stable operation across transient and part-load regimes while mitigating thermal NOx formation and thermoacoustic instabilities.