CFD simulation of contrail formation in the near field of a commercial aircraft: Effect of fuel sulfur content

Abstract

Aircraft contrails may contribute to the global radiative forcing. In this context, the investigation of contrail formation in the near field of an aircraft may be helpful in developing strategies to reduce undesirable impacts. In this study, three-dimensional Reynolds-Averaged Navier-Stokes (RANS) simulations of contrails produced by commercial aircraft during cruise flights were performed. A realistic geometry (herein a Boeing 737) was taken into account, including the engine core and bypass flows, which allows several parametrical studies and avoids using parameterizations to describe the plume's dilution. The objective was to simulate the early development of contrails in a fresh plume whose dilution was obtained with a spatial simulation of jet/vortex interaction. A coupling was carried out with a chemical and a microphysical model implemented in the numerical simulation code CEDRE to simulate particle growth using an Eulerian approach. The implemented microphysics model can simulate water condensation onto soot particles, taking into account their activation by adsorption of sulfur species. Our simulations show that sulfur dioxide is converted into sulfur trioxide and sulfuric acid at a rate of conversion close to 3 %, which is in good agreement with other studies. Ice-crystal growth was faster when the fuel sulfur content (FSC) increased, allowing a visible contrail to appear earlier. These promising results confirm in situ observations and highlight the model's ability to simulate typical plume chemistry and complex microphysics/chemistry interactions coupled with detailed jet/vortex dynamics.

Keywords

• Contrail
• soot
• activation
• sulfur
• simulation