Session: 01-10 Modelling, Simulation and Validation II

Paper Number: 124447

124447 - Assessing the Environmental Impact of Aircraft / Engine Integration With Respect to Contrails 

Radiative forcing due to engine emission is one of the most serious impacts of aviation. While CO₂ emissions have received the majority of attention in past years, there is growing evidence that the short term effective radiative forcing due to non-CO₂ terms could be twice that of the CO₂ contribution, with contrails and contrail cirrus being responsible for the majority of this additional forcing. From an air vehicle design perspective, the urgency of climate change and sustainability issues demonstrate that there is a need to better understand emissions and their impacts with respect to contrail formation for both current and next generation aircraft.

A contrail microphysics module has been developed using an Eulerian modelling approach and has been integrated within the in-house HYDRA CFD code to be used within power-on aircraft simulations. The model focusses on the formation, growth, and sublimation of ice aboard atmospheric particulates. For hydrocarbon burning aircraft, these particulates predominantly consist of soot particles which are emitted from the core of a jet engine. Contrail properties can be assessed in the near-field exhaust extending into the vortex regime, which extends approximately 100 seconds behind the aircraft. Past the vortex regime, contrail dynamics are dictated by atmospheric conditions.

Our preliminary work suggested that airframe geometry and engine integration can have a significant impact on contrail formation and resultant particle properties. To understand the potential relationships between contrail properties and aircraft design, a parametric aircraft model closely representative of a modern medium to long haul airliner with a realistic dual-flow nozzle incorporated within the nacelle is built. This allows a range of aircraft configurations to be simulated within HYDRA CFD, including future concept designs which place the engine closer to the aircraft centreline aiming to utilise fuselage boundary layer ingestion to improve efficiency. Between configurations, varying levels of interaction with the aircraft’s external aerodynamics and the influence on mixing within the exhaust plume have been assessed which allows the impact on contrail properties to be understood in greater detail. It is found that the wingtip vortex has significant interaction with the exhaust plume and therefore impact on the produced contrail’s properties and dynamics as it persists. Multi-engine architecture also influenced the contrail as levels of entrainment between exhausts into the vortex were affected. This work opens the door to explore how potential design changes to current and concept aircraft could reduce their environmental impact.

Presenting Author: Joseph Ramsay Rolls Royce plc

Presenting Author Biography: PhD student in the Department of Mechanical Engineering at the University of Sheffield, sitting within the Future Methods team in Rolls Royce, Derby.

Authors:

Joseph Ramsay Rolls Royce plc
Indi Tristanto Rolls Royce plc
Shahrokh Shahpar Rolls Royce plc
Alistair John University of Sheffield