Influence of Fuel Sulfur Content and nvPM Emissions on Contrail Formation: A CFD-Microphysics Approach

A CFD-microphysics coupling approach is presented for accurately predicting the formation and evolution of ice crystals originating from soot and volatile particles in the near-field of a turbofan engine. This method integrates an online Eulerian–Lagrangian coupling based on 2D axisymmetric unsteady Reynolds-Averaged Navier–Stokes equations to simulate exhaust plume dynamics. The framework incorporates tabulated chemistry (including 60 reactions, 22 reactive species, and 29 non-reactive species) and a detailed ice microphysics model. The model accounts for complex multicomponent interactions, including soot surface activation, condensation of organic vapors and sulfur species (H₂SO₄, SO₃), and the scavenging of sulfuric acid-water droplets by soot surfaces.

The analysis examines the effects of varying ambient temperatures, fuel sulfur content, and soot particle concentrations on ice crystal formation, which will be discussed in detail.

As a result, the figure compares the spatial distributions of plume particles, focusing on the effects of ambient temperature and fuel sulfur content. Specifically, it examines the spatial distribution of soot particles in three states: dried (black), activated (blue points), and frozen (cyan points). The comparison is presented for two scenarios:
a) ambient temperatures of 212 K and 218.8 K at a sulfur content of 700 ppm, and
b) sulfur contents of 700 ppm and 20 ppm at an ambient temperature of 218.8 K.

a)

b)