Effects of wall temperature on non-premixed micro-combustion: A comparative experimental study of copper and aluminum in Swiss-roll chambers

Micro-combustors, vital for compact power and propulsion, face significant challenges in maintaining flame stability and achieving high blow-off limits. This study experimentally investigated counterflow non-premixed methane‑oxygen combustion in an innovative Swiss-roll chamber, examining bodies crafted from copper, aluminum, and steel at varying wall temperatures. Our primary objective was to thoroughly evaluate how these distinct body materials impact flame dynamics and overall micro-combustion performance. We utilized advanced diagnostic techniques, including spectroscopy and RGB image processing, for detailed analysis. Results showed copper's inherent catalytic properties notably enhanced combustion, with radical radiation intensity increasing by up to 30 % as chamber temperature rose. Conversely, in the aluminum chamber, surface adsorption of radicals by the formed alumina layer hindered radical radiation, weakening it with rising temperature. Notably, no flame was observed in the steel chamber. These findings unequivocally demonstrate the profound influence of body material on micro-combustion performance. This research offers valuable, material-specific insights crucial for the optimal design and precise optimization of next-generation micro-combustion devices, guiding material selection for enhanced efficiency and reliability in applications like micro-thermophotovoltaic systems and micro-thrusters. • Copper enhances methane combustion efficiency due to its thermal and catalytic properties. • Flame length reaches a maximum at an equivalence ratio of 0.5 and decreases at higher ratios. • Wall material and temperature affect radical emissions; copper boosts emission intensity as temperature rises. • Copper enhances combustion intensity, whereas aluminum shows decreased intensity with increasing temperature. • RGB image analysis correlates light intensity and color with specific combustion properties.