Modélisation numérique de la dynamique des fluides du procédé de dégivrage au sol des aéronefs par liquide de dégivrage

Abstract

The aircraft ground deicing process is mandatory for all types of aircraft to take-off in icing conditions. In the early days aircraft were deiced by a purely mechanical operation. In the 1950s the industry moved toward the use of deicing solutions. Nowadays, the process is well defined by the Society of Automotive Engineers (SAE) international global anti-icing and deicing standards. However, several process parameter values are not defined which leads the process efficiency to dependent on the operator’s level of expertise. This research proposes numerical methods allowing the use of computational fluid dynamics (CFD) for the simulation of the aircraft ground deicing process. These numerical methods have been implemented in a CFD code and have been verified. This work is presented in the form of a thesis by article. The numerical methods are published through three journal articles and served to develop the CFD code. The first paper presents a Eulerian-Lagrangian model of aircraft ground deicing that avoids the scale dispersion problem caused by the considerable distance between the spray nozzle and the surface to be de-iced. Verifications are done using a testcase of a hot particle liquid spray impinging on a horizontal flat plate. The computed wall heat distribution is verified. In the end, an inclination spray angle study is presented. The second paper focuses on the region at the vicinity of the ice where it proposes a CFD method to simulate the interaction between ice and the hot aircraft deicing fluid. A particulate two-phase flow approach is used to model the spray impact on ice near the contaminated surface. Ice melting is modelled using an extended version of the enthalpyporosity technique. The water resulting from the melting process is diffused into the deicing fluid forming a single-phase film. This paper presents a new model of the process. The model is verified and validated through three steps: (i) verification of the species transport, (ii) validation of the transient temperature field of a mixture, (iii) validation of the convective heat transfer of an impinging spray. The permeability coefficient of the enthalpy-porosity technique is then calibrated. The proposed model proved to be a suitable candidate for a parametric study of the aircraft ground deicing process. The third paper is a combination of the first two where it presents a 3 dimensions CFD method to simulate the process in full scale. The method comprises a multi-region model where a Lagrangian method solves the spray particle equations, and the enthalpy porosity simulates the ice melting with an Eulerian method. The multi-region approach is verified in this paper through a spray-tip penetration (STP) test. The STP predicted by the multi-region model agrees at 99% with the STP predicted by a Lagrangian model. Therefore, the multi-region correctly transfers the particle momentum between the two regions. The three papers led to a CFD code specially designed and verified to simulate the aircraft ground deicing process. Optimal deicing scenarios can be defined by investigating the effect of spray parameters on deicing efficiency. This code could also be used to design a simulator for training agents.

Date	7 Mar 2023
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	François Morency (Supervisor)