Work

Thermodynamic evaluation of contrail formation from a conventional jet fuel and an ammonia-based aviation propulsion system

Year: 2024

Type: article

Abstract: This study evaluates the potential of a newly introduced carbon-free, ammonia-powered propulsion system in contrast to conventional propulsions powered by jet fuel in forming condensation trails (contrails). Contrail formation in an airplane's wake relies on two main prerequisites. Firstly, the system's thermodynamics must lead to supersaturation. Secondly, aerosol particles must be present to provide surfaces for solidification, enabling the formation of visible ice crystals. While this study primarily analyzes the first requirement, it leverages the insights gained to comment on the second prerequisite, arguing that although ammonia does not generate soot particles, it dramatically warms the critical temperature required for supersaturation. Therefore, given that aerosol particles are consistently generated or released into the atmosphere through natural and human-made processes, which is why natural clouds can form anyway, increased critical temperatures caused by ammonia result in contrails that would not occur if jet fuel were employed. Hence, while ammonia's contrail might not be as dense as jet fuel's as it lacks soot particles in the exhaust gas, it can form at lower altitudes where the air is warmer. Moreover, it can endure longer due to the increased water content, which preserves supersaturation for longer as fresh air dilutes the contrail.

Source: Communications Engineering

DOI: 10.1038/s44172-024-00312-2