The impact of contrails on the radiative budget balance is now admitted in the scientific community, but hardly to quantify. In this context, this research work aims to study the formation of contrails in the near field of an aircraft.
Computational fluids dynamics (CFD) is the tool used in this study. The Unsteady Reynolds-Averaged Navier Stokes (URANS) equations are solved for the gaseous phase in the turbulent and compressible regime. Indeed, an Eulerian approach for the gaseous phase composed of air and water vapour is in interaction with the solid phase composed of passive particles. This latter represent soot particles issued from the engine combustion and ice crystals relying on a Lagrangian approach. Ice crystals growth is calculated by the mathematical model of Fukuta and Walter computed in the commercial software STAR-CCM+.
The results show the influence on the bypass flow on aerothermodynamics properties of the plume and microphysics properties of ice crystals. The turbulent kinetic energy is low from the first moment of the plume and ice crystals are formed later with the bypass configuration. However, that the turbulent kinetic energy increase with downstream distance behind the engine and the temperature drop quickly in the edge of the jet, where the turbulence is maximale. The number and size of ice crystals were higher at the end of the computational domain with the bypass flow configuration. Moreover, parametric studies were carry on so as to evaluate the influence of engine exit parameters (initial particles number, initial particles radius, water vapour quantity) and atmospheric (ambient temperature, ambient relative humidity) on the microphysical properties of ice crystals. For example, the results of the parametric study show that a colder ambient temperature of 9K significantly affects the mean ice crystals radius (+160.35 %) and the number of ice crystals formed (+24,54 %).
| Date | 5 Nov 2018 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | François Garnier (Supervisor) & François Morency (Co-supervisor) |
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Cantin, S. (Author),
Garnier (Supervisor) &
Morency (Co-supervisor),
5 Nov 2018Student thesis: Master's thesis › Master in Engineering: Mechanical Engineering