COMPARATIVE STUDY ON THE PERFORMANCE OF A SWIRL-TYPE BURNER CAP FOR DOMESTIC GAS GEYSERS

Abstract

Enhancing combustion efficiency in domestic gas geysers is essential for reducing fuel consumption and pollutant emissions. This study presents a comparative experimental investigation of a conventional swirl burner cap and a newly designed perforated 45° swirl-type burner cap for residential gas geysers. The modified burner cap was developed using a combined CAD-based design, sand casting, and CNC machining approach to ensure manufacturability and geometric precision. Performance evaluation was conducted on a domestic geyser test rig using real-time flue gas analysis and standardized combustion efficiency calculations. For the conventional swirl burner cap, the measured flue gas composition showed 8.40% O₂, 6.82% CO₂, and 0.0051% CO, with a stack temperature of 540.7 °C, resulting in a combustion efficiency of 68.41%. In contrast, the perforated swirl burner cap exhibited a significantly improved performance, with an average O₂ concentration of 11.80 ± 0.12%, reduced CO₂ concentration of 4.47 ± 0.40%, and CO emissions of 0.0045%. The stack temperature decreased substantially to 276.1 °C, indicating lower flue gas losses. Consequently, the modified burner achieved a higher average combustion efficiency of 82.03 ± 0.15%, representing an improvement of approximately 14% compared to the conventional design. The enhanced performance is attributed to improved air–fuel mixing and intensified turbulence generated by the hole-assisted swirl configuration. The results demonstrate that geometric modification of burner caps offers a simple, cost-effective solution for improving combustion efficiency and reducing emissions in domestic gas geysers. This study provides practical insights for the development of energy-efficient household heating appliances.