HYDEA Project Work Package 6: Contrail modeling for hydrogen combustion.

Aviation emissions contribute to climate change, one of the key contributors being contrail cirrus clouds. The importance of this impact is strongly dependent on their properties . 

A condensation trail - or contrail - is composed of ice crystals which form behind the aircraft engine exhaust at high altitudes when local weather conditions are favorable. The formation is also influenced by the engine technology and operating conditions, and by the fuel type. The contrail persists and evolves as long as it remains in an ice supersaturated region, a local atmospheric air mass characterized by a low temperature and a humidity level that is saturated versus ice. Only persistent contrails are considered as having a climate effect.

Hydrogen propulsion is considered as one promising technology to reduce aviation’s climate impact, in line with the European Green Deal and Clean Aviation Strategic Research and Innovation Agenda (SRIA). In this context, the EU-funded HYDEA project proposes a robust and efficient technology maturation plan for H2 propulsion. 

The formation of contrail ice crystals in an aircraft plume is mainly driven by the interaction of three physical phenomena: the dynamics in the engine exhaust, chemical transformations of effluents and microphysical processes.

The main assumptions when moving from a kerosene to a H2 fueled propulsion system are that there will be no soot particles in the jet exhaust, and an increased water vapour emission compared to kerosene. New modelling chains are required to understand how, in this case, ice crystals are formed and they evolve.

The models under development will be presented along with the assumptions being made. In HYDEA Work Package 6, two H2 contrail models using complementary methods are under development, using the Common Research Model [1]. The ONERA model using the 3D model CEDRE for both jet and vortex phases simulation provides a high-fidelity engine and aeroplane representation. The DLR model uses a Lagrangian Cloud Module box model approach with particle-based microphysics providing a high-fidelity microphysical representation with a simplified geometry. This ingests jet exhaust CFD data provided by Airbus and GEAP. The latest scientific developments and assumptions being incorporated in the models are discussed.

[1] Development of a Common Research Model for Applied CFD Validation Studies: J. Vassberg, M. Dehaan, M. Rivers & R. Wahls. 26th AIAA Applied Aerodynamics Conference 2012, June 2012, Hawaii, United States. https://doi.org/10.2514/6.2008-6919.