Modelling the chemical entropy and exergy balance during single-step chemical reactions and its application to an inverse-diffusion ethylene flame
FUEL, cilt.428, sa.Part B, ss.1-20, 2027 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 428 Sayı: Part B
- Basım Tarihi: 2027
- Doi Numarası: 10.1016/j.fuel.2026.140325
- Dergi Adı: FUEL
- Derginin Tarandığı İndeksler: Academic Search Ultimate (EBSCO), Engineering Source (EBSCO), Scopus, Science Citation Index Expanded (SCI-EXPANDED), Chemical Abstracts Core, Chimica, Compendex, INSPEC
- Sayfa Sayıları: ss.1-20
- Gazi Üniversitesi Adresli: Evet
Özet
This paper presents a model for energy conversion and derives an exergy balance equation for single-step chemical reactions in flames. The model can evaluate changes in chemical and thermodynamic energy, the loss of available energy, and thermodynamic efficiency. By combining this model with a detailed chemical mechanism, the effects of pressure, temperature, and the equivalence ratio on exergy efficiency are evaluated. In addition, important chemical reactions and substances for energy conversion can be identified. Furthermore, this model is applied to the thermodynamic analysis of an inverse-diffusion ethylene (C2H4) flame. A systematic study, including entropy generation, chemical analysis, and exergy analysis, is carried out. The combustion and thermodynamic characteristics of the inverse-diffusion C2H4 flame are investigated. The results indicate that increasing the temperature of the medium is a relatively direct and effective way to improve exergy efficiency. The pyrolysis and oxidation of C2H4 are the main sources of the chemical entropy generation rate (EGR), while multi-carbon reactions contribute very little. The pathways C2H4 → C2H3 → CH2 → (CH2O or CH) → HCO → CO are the most important for the chemical EGR. From the inner to the front of the flame, thermodynamic equilibrium is established, and a low temperature is a more significant factor limiting reactions than reactant concentration. Five reactions (R12, R48, R60, R77, and R55) determine the energy conversion efficiency of the entire flame. These reactions account for more than 95 % of energy conversion and should be emphasised when optimising combustion.