THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

Xiangyun Liu

,

Zhu Liang

,

Liangde Liu

,

Xiufang Ke

,

Haitao Zheng

online first only

Combustion characteristics of dual swirl low nitrogen burners in small gas boilers

ABSTRACT
Swirl combustion technology is an effective method for achieving low-nitrogen (low NOx) combustion. In this study, we designed a dual-swirl low-NOx burner with the goal of minimizing NOx emissions. and the burner was evaluated in a 20t/h gas boiler through numerical simulation and experimentation. Swirl angles and excess air coefficients (1.0 to 1.20) of the burner were tested within the range of 1.0 to 1.2. The results indicated that the optimal swirl plate angles were 35° internally and 55° externally. The optimal excess air coefficient was 1.15, which balances heat transfer efficiency and minimize NOx emissions. Results show that the dual swirl combustion system can effectively reduce nitrogen oxide emissions in small gas boilers.
KEYWORDS
Dual-swirl low-NOx burner, Gas boiler, excess air coefficient, Central air ratio
PAPER SUBMITTED: 2025-03-26
PAPER REVISED: 2025-08-13
PAPER ACCEPTED: 2025-08-14
PUBLISHED ONLINE: 2025-09-13
DOI REFERENCE: https://doi.org/10.2298/TSCI250326152L
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Combustion characteristics of dual swirl low nitrogen burners in small gas boilers