Optimization effect of propylene oxide (PO) on evaporation, combustion, and pollutant emissions of high-energy–density JP-10 fuel

Abstract

JP-10 is a high-energy–density fuel that is widely used in aerospace propulsion systems due to its wide range of synthetic raw materials and low production costs. However, it faces challenges related to difficult ignition, low combustion efficiency and high pollutant emissions. To address this, blending JP-10 with propylene oxide (PO), a highly volatile substance, provides a practical solution. This study investigates the propagation and evolution characteristics of JP-10/PO binary fuel in large horizontal pipelines. The results demonstrate a synergistic enhancement effect achieved by the JP-10/PO hybrid fuel. PO, with its lower boiling point, quickly evaporates from the mixed droplets, creating a continuous primary flame. As the droplet temperature increases, JP-10, known for its high combustion heat, starts to evaporate, actively participating in the explosion process and forming a secondary flame that spreads in two directions. The combustion of the JP-10/PO mixed droplets involves both physical and chemical processes, including droplet evaporation and gaseous combustion. A binary droplet evaporation model is developed to quantitatively assess the impact of PO fuel ratio on spray evaporation. Additionally, the study examines steam explosion parameters and reaction product characteristics under different PO fuel ratios. It is observed that the evaporation of JP-10/PO mixed droplets occurs in three stages: transient heating, binary equilibrium evaporation, and single component equilibrium evaporation. Increasing the PO fuel ratio leads to a higher temperature rise rate of the droplets and an increased evaporation reaction rate constant. Moreover, the ignition delay time of JP-10/PO gas-phase mixture fuel decreases, while the adiabatic flame temperature gradually reduces. Furthermore, higher PO fuel ratios help reduce the emissions of unstable products in both mixed fuels due to the inherent oxygen content of PO molecules. The current research results can provide scientific references for the improvement of high-energy density fuels and the development of new propellants.