Experimental and kinetic study of propane combustion with C2 additives using a custom-designed burner

Propane (C 3 H 8 ) is a widely used gaseous hydrocarbon fuel, but incomplete combustion can generate hazardous intermediates, including carbon monoxide (CO) and formaldehyde (CH 2 O). This study investigates the effects of ethylene (C 2 H 4 ) and acetylene (C 2 H 2 ) addition on propane combustion using an externally cooled, self-designed gaseous-fuel burner, spontaneous Raman scattering (SRS), and CHEMKIN calculations. Additive fraction (0–30 %), equivalence ratio (φ = 1.2–2.0), and measurement height (15–95 mm) were varied. At φ = 2.0 and a measurement height of 15 mm, a 30 % C 2 H 4 additive fraction produced a CO Raman count above 1600, whereas 30 % C 2 H 2 yielded approximately 1100. The CH 2 O signal reached a maximum near 20 % C 2 H 2 and a minimum near 20 % C 2 H 4 ; both fitted signals approached approximately 800 counts at an additive fraction of 30 %. For flames with 20 % additive, the fitted CO and CH 2 O crossover heights were 31.8 and 35.0 mm, respectively. The calculations indicate that C 2 H 4 favors comparatively direct addition–oxidation and H/O/OH chain-branching pathways, whereas C 2 H 2 shows stronger competition between oxidation and carbon-growth chemistry. Together, the measurements and simulations show that the molecular structure of the C 2 additive and flame position jointly control local intermediate-species accumulation, although the homogeneous-reactor calculations should be interpreted at the trend level.