Numerical Simulation of Contrail Ice Particle Growth in the Near Field of an Aircraft Engine

Contrails from aircraft may have a direct impact on the Earth’s radiative budget balance. The aim of this study is to examine the formation of contrails in the near field of a realistic configuration based on the CFM56 engine and consequently, on the soot and ice particles evolution. In this work, we focused on a primary exhaust jet laden with soot particles and mixed with a secondary jet (bypass flow) in the cold ambient air. The study has been performed using a 2D axisymmetric CFD calculation based on an URANS (Unsteady Reynolds Average Navier-Stokes) approach. Numerical simulations have been performed using STAR-CCM+, a commercial code for multiphysics. The particles are tracked using the Lagrangian approach. A microphysical model was used to calculate their growth. The results show the evolution of ice crystal sizes throughout the exhaust jets. As an example, the mean particle radius grows up to approximately 0.7 μm 0.5 s downstream in agreement with experimental data