Xiangyun, LZhu, LLiangDe, LXiuFang, KHaitao, Zheng2026-02-182026-02-1820250354-98362334-7163https://doi.org/10.2298/TSCI250326152Lhttp://hdl.handle.net/10204/14691Swirl 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.FulltextenDual-swirl low-NOx burnerGas boilerExcess air coefficientCentral air ratioArticlen/a