Simulation of volcanic ash ingestion into a Large Aero Engine

Author(s)
Andreas Vogel, Adam J. Durant, Massimo Cassiani, Rory J. Clarkson, Michal Slaby, Spyros Diplas, Kirstin Krüger, Andreas Stohl
Abstract

Volcanic ash (VA) clouds in flight corridors present a significant threat to aircraft operations as VA particles can cause damage to gas turbine engine components that lead to a reduction of engine performance and compromise flight safety. In the last decade, research has mainly focused on processes such as erosion of compressor blades and static components caused by impinging ash particles as well as clogging and/or corrosion effects of soft or molten ash particles on hot section turbine airfoils and components. However, there is a lack of information on how the fan separates ingested VA particles from the core stream flow into the bypass flow and therefore influences the mass concentration inside the engine core section, which is most vulnerable and critical for safety. In this numerical simulation study, we investigated the VA particle-fan interactions and resulting reductions in particle mass concentrations entering the engine core section as a function of particle size, fan rotation rate, and for two different flight altitudes. For this, we used a high-bypass gas-turbine engine design, with representative intake, fan, spinner, and splitter geometries for numerical computational fluid dynamics (CFD) simulations including a Lagrangian particle-tracking algorithm. Our results reveal that particle-fan interactions redirect particles from the core stream flow into the bypass stream tube, which leads to a significant particle mass concentration reduction inside the engine core section. The results also show that the particle-fan interactions increase with increasing fan rotation rates and VA particle size. Depending on ingested VA size distributions, the particle mass inside the engine core flow can be up to 30% reduced compared to the incoming particle mass flow. The presented results enable future calculations of effective core flow exposure or dosages based on simulated or observed atmospheric VA particle size distribution, which is required to quantify engine failure mechanisms after exposure to VA. As an example, we applied our methodology to a recent aircraft encounter during the Mt. Kelud 2014 eruption. Based on ambient VA concentrations simulated with an atmospheric particle dispersion model (FLEXPART), we calculated the effective particle mass concentration inside the core stream flow along the actual flight track and compared it with the whole engine exposure.

Organisation(s)
Department of Meteorology and Geophysics
External organisation(s)
Norwegian Institute for Air Research, University of Oslo, Satavia Ltd., Michigan Technological University, Rolls-Royce plc, SINTEF The Foundation for Scientific and Industrial Research at the Norwegian Institute of Technology (NTH)
Journal
Journal of Turbomachinery
Volume
141
ISSN
0889-504X
DOI
https://doi.org/10.1115/1.4041464
Publication date
01-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
105206 Meteorology
ASJC Scopus subject areas
Mechanical Engineering
Portal url
https://ucrisportal.univie.ac.at/en/publications/19f1e29d-7472-42f3-a4b7-f0c247f4e149