Optimizing Candle Shapes for Maximum Flame Luminosity and Minimal Wax Residue

Abstract

Combustion processes are among the most widely used energy conversion methods, with candles as a small-scale example. As with similar processes, energy efficiency in candles is often sought. While previous studies have independently investigated the behavior of candle flames, burning wax, and air flows, an optimized relationship between all three remains underexplored. This study aims to investigate candle shapes that maximize flame luminosity and to explore the shapes resulting in minimal wax residue. To investigate the former, the relationship between luminosity and wax pool radius will be explored through both theory and experimentation. Then, for the latter, the growth rate of the wax pool as a function of time will be theoretically and experimentally studied. Candle shapes will be predicted based on the previous results and fluid dynamics theory. They will then be tested and compared. Preliminary results show that an inverted paraboloid-shaped candle produces the most luminous flame, and thin cylindrical candles (radius ~1cm or less) limit wax residue the most, but more trials will be recorded to ensure accuracy of these results and explore more shapes. This study’s limitations include measurement precision affected by environmental factors like natural air currents, even in a controlled setting, and the limited number of candle shapes that can be tested, which might not fully capture the most optimal geometries. Regardless of the specific findings, this study will contribute to a better understanding of small-scale combustion processes, with potential applications in energy efficiency, more sustainable candle designs, and fluid dynamics research.