PG-EAM - Graduate Program in Aeronautical and Mechanical Engineering
PT EN
PhD Thesis 2025

A comprehensive study of limonene combustion characteristics and its potential as a sustainable aviation fuel

Author

Luis Fernando Marcondes Garzón Lama

Concentration Area

Propulsão Aeroespacial e Energia

Defense Date

04/07/2025

Thesis Number

80525

Abstract

Limonene, a terpene naturally found in pine trees and citrus fruits, exhibits combustion characteristics that make it a promising candidate as an aviation fuel additive. With a carbon range within C9-C16, a flash point above 38°C, a crystallization temperature near -76°C, and an energy density of approximately 45 MJ/kg, it aligns well with Jet A-1 specifications. Experimental measurements of laminar burning velocity (LBV) were performed in spherical and cylindrical constant-volume reactors at 1 bar and initial temperatures of 358 K, 398 K, and 438 K, using Schlieren imaging. Tests included pure limonene, the MURI 1 surrogate for Jet A-1, and a 70/30 MURI 1-limonene blend across equivalence ratios from 0.7 to 1.3. Pure limonene exhibited a high SL, peaking at 70 cm/s, exceeding that of conventional kerosene. When blended with MURI 1, SL increased to intermediate values, with a maximum enhancement of 8% under fuel-rich conditions. Numerical simulations based on a newly proposed kinetic mechanism derived from JetSurF 2.0 showed good agreement with experimental SL data, with a maximum deviation of 6% at ?? ? 1.1 and 438 K. Slight underprediction was observed at ?? ? 1.3 and 358 K, and overprediction at higher temperatures. Flame stability analysis revealed that limonene flames become less stable under richer conditions due to reductions in Markstein length and Lewis number. However, the addition of limonene to MURI 1 improved flame stability by increasing Lb, despite a slight decrease in flame thickness. The validated kinetic model successfully reproduced ignition behavior and the formation of major combustion products (CO?, H?O, CO, H2) and key intermediates (C6H6, CH4, C2H2), confirming both the robustness of the mechanism and the viability of limonene as a sustainable aviation fuel additive.

Keywords

Combustão Velocidade de queima Combustíveis alternativos Propagação de chama Desenvolvimento sustentável Engenharia química