Flame stabilization and combustion performance of swirl-stabilized shower burners under LPG-to-CNG substitution: CFD and experimental analysis

• CFD–experimental study of LPG, CNG, and swirl-stabilized shower burners. • Swirl raised turbulence above 190 % and peak flame temperature to 1523 K. • Combustion efficiency exceeded 95 % with CO emissions as low as 291 ppm. • CFD predictions matched experimental results within 7 % error. • Industrial relevance confirmed via LPG-to-CNG substitution in ceramic kilns. Ceramic kilns in Southeast Asia remain heavily dependent on liquefied petroleum gas (LPG), a carbon-intensive fuel that often produces unstable combustion in shower-type burners. This study provides a novel contribution by delivering a kiln-scale experimental dataset and a validated CFD framework specifically developed to evaluate LPG-to-CNG substitution in these industrial burners—an area sparsely addressed in existing literature. Simulations, validated against measured velocity and temperature fields with errors below 7 %, show that direct CNG substitution improves premixing and increases turbulence intensity, resulting in more compact and stable flames. Incorporating swirl yields the most significant enhancement, generating turbulence levels of 180–193 %, peak temperatures of 1450–1523 K, combustion efficiencies above 95 %, and CO emissions as low as 291 ppm, while maintaining NO x within 26–98 ppm. An economic assessment further demonstrates clear industrial benefits, with annual fuel savings of approximately 505 USD and a payback period of 2.65 years. Overall, this integrated CFD–experimental investigation establishes swirl-assisted CNG combustion as an effective and practically viable retrofit strategy for improving stability, efficiency, and emissions performance in ceramic kiln burners.