Thermal behaviour and combustion characteristics of JET A-1, HEFA-derived SAF and their blends for aeronautical applications
Résumé
Thermal and combustion characteristics of aviation fuels are useful in system design for combustors and modelling for engine design and their performance. This study investigates the thermal behaviour and combustion properties of pure JET A-1 (J100), HEFA-derived SAF (HS100) and its blends (JxHSy) using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) techniques. The analyses were supported by compositional evaluation with gas chromatography-mass spectrometry (GC-MS) and the fuel properties were compared according to ASTM standards. Thermal stability and mass loss rates showed gradual degradation patterns for HS100, while J100 revealed sharper, more rapid degradation. J100 degraded between 85°C-168°C, and HS100 degraded between 100°C-205°C, indicating improved thermal stability for HS100. HS100 displayed higher energy density, lower viscosity, and a broader exothermic peak, enabling cleaner combustion and extended engine life. DSC analysis revealed distinct thermal peaks: J100 has an endothermic and exothermic peak at 218°C and 234°C, respectively, while HS100 showed a broader endothermic and exothermic peak at 231°C and 248°C, respectively. J30HS70 blend exhibited intermediate peak values, combining the thermal advantages of both components. The enthalpy values are J100 (−90.53 J/g), HS100 (−69.68 J/g) and J30HS70 (−167.90 J/g). For combustion indices, J100 has the highest comprehensive performance index (2.10 × 10⁻⁶ mass²/min² °C³) and ignition index (3.50 × 10⁻⁴ mass/min °C²). The lowest values for both indices were found for HS-rich blends, attributed to their lower aromatic and higher paraffinic compositions. From GC-MS analysis, J100 showed 45% low-molecular-weight alkanes C8–C15 while HS100 had only 21%, contributing to HS100’s cleaner combustion characteristics. The findings confirm that HEFASAF and its blends are promising sustainable alternatives for aviation, offering thermal stability, cleaner combustion, and environmental benefits. Future studies on modelling combustion dynamics and emissions in real-world jet engines would provide deeper insights.