Journal: Case Studies in Thermal Engineering, vol. 73, pp. 106485, 2025.
Title: Comparison of O2-enriched and N2O oxidizers on dual-flame structure and entropy generation
Authors: Yueh-Heng Li*, Po-Hung Lin, Wen-Yuan Tsai, Janusz Lasek
Rank: 7.6% (6/79), SCI, THERMODYNAMICS, 2024.
Impact Factor: 6.4
Abstract: This study utilizes a triple concentric burner to generate a dual-flame structure and investigates the impact of dual flames on entropy generation under varying fuel-oxidizer velocity ratio (R), ultimately identifying the dominant pathways. The study also examined the substitution of nitrous oxide (N2O) with a nitrogen-oxygen (N2−O2) mixture to understand the influence of N2O decomposition on entropy generation. The research evaluated the irreversibility of chemical reactions in the presence of a dual-flame structure. It was observed that the chemical reaction term in the N2O case (R = 3) was approximately twice as intense as in the O2-enriched case (R = 5) due to the more vigorous reaction of N2O, despite similar energy input. Reactions involving N2O, such as those related to the cyanato radical (NCO) and isocyanic acid (HNCO), were slightly more pronounced in the N2O case compared to the O2-enriched case, even though the R ratio was lower in the N2O case. In conclusion, increased entropy generation reduces exergy and decreases second-law efficiency (ηII) from 88.5 % to 78.8 % in O2-enriched cases and from 74.3 % to 66.3 % in N2O cases as R increases. This decrease is more pronounced in dual-flame structures, where ηII drops below 80 %, primarily due to heat conduction and chemical reactions.
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