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Knowledge for Ignition, Acoustics and Instabilities

Final Report Summary - KIAI (Knowledge for Ignition, Acoustics and Instabilities)

Executive Summary:

Air traffic is expected to grow over the next 20 years annually by respectively 3-5% for passengers and 9-10% for freight (ACARE1 "average" scenario). This traffic growth will continue to negatively impact the environment with increased greenhouse effects (CO2 emissions) and degradation of local air quality (NOx but also soots, particulates and CO emissions as well as UHC).
The engine emissions issue is addressed by the evolution of the relevant international regulations (e.g. ICAO CAEP2 standards) and by ambitious technological objectives agreed by the European aeronautics industry described in "Vision 2020" of the 2nd version of the ACARE Strategic Research Agenda ("SRA2")2.
Availability of clean engines not only has a huge environmental impact, but has also become a vital stake for every manufacturer to maintain a position within world competition for sustainable growth of aviation transport. Developing combustion technologies for clean engines is consequently necessary to comply with the ambitious ACARE 2020 targets and future ICAO standards, to gain new markets and to remain competitive ahead of non-European manufacturers.
The European engine industry has been addressing engine emissions for many years in several very ambitious R&T projects, particularly in the EC framework programmes 5 and 6. Lean combustion technologies have proven in R&T projects (LOPOCOTEP, TLC, INTELLECT D.M EEFAE, NEWAC and CLEAN) their high potential for achieving the overall NOx reduction targets and for reducing particulates. Nevertheless, the potential of low NOx technologies is facing the problem of managing new technologies that are fundamentally sensitive to unsteady behaviour like combustion instabilities, quenching,, ignition or engine re-light.
For the time being, the European engine industry does not have at its disposal methodologies adapted to predict behaviour of low NOx combustors. Consequently and in order to be able to set up the development of low NOx technologies, KIAI will deliver unstationary CFD tools which will allow a deep comprehension of unsteady phenomena.
The main objective of the KIAI project is to provide reliable methodologies to predict the stability of industrial low NOx combustors, as well as their ignition process from spark to annular combustion.
When used at an early stage in the conception cycle of low NOx combustors, KIAI CFD methodologies will play a key role and considerably accelerate the delivery process of lean combustion technology with a proven capability to reach 80% NOx emission reduction required for introduction into service before 2020 with the necessary reliability, safety and economical viability.
As already demonstrated by past and ongoing studies and European projects low NOx technologies lead to crucial unsteady phenomena that are neither controlled nor predictable at the moment.

The scientific objectives of KIAI are directly linked to providing a better understanding and prediction of these unsteady phenomena by:
- predicting the coupling between the acoustics and the flame
- determining the acoustic boundary conditions of multiperforated plates surrounding the combustion chamber
- accounting for non-premixed spray flows in the combustion process.
- exploring aerodynamic unsteadiness in strutted pre-diffusers adapted to high mass flow injectors and develop a liquid film break-up model for an injector
- evaluating the ability for LES to help to make the final decision between two similar geometries in the design process of low NOx combustors

The main expected outputs of KIAI derived from the scientific objectives are:
- Acoustic tools able to provide stability maps of the combustors including the influence of the flame
- An acoustic description of multi-perforated plates widely encountered in combustion chambers
- A tabulated chemical description of non-premixed spray combustion
- A liquid film break up model
- An estimation of the reliability of LES with respect to its capacity to account for small technological variations of geometry for both isothermal and reactive flows

Project Context and Objectives:
Table included in the PDF
Project Results:
Table included in the PDF, chapter 2 and 3
Potential Impact:
Table included in the PDF, chapter 4
List of Websites:
The KIAI consortium gathers 18 organisations – academia, research institutes and SMEs – from 4 countries. Each of these partners has been carefully selected to bring particular expertise or facilities to the consortium. They share a common interest in advancing combustion research by developing innovative technologies, and collaborate in an integrated, synergistic approach leading to results that would not be achievable by any of the partners on its own.
The KIAI consortium is composed of the following organisations:
• SNECMA, SN
• Turbomeca, TM
• Rolls Royce Deutschland Ltd & Co KG, RRD
• Rolls-Royce plc, RRUK UK
• AVIO S.p.A AVIO
• INSA de Rouen - UMR 6614, CORIA
• Centre National de la Recherche Scientifiques, CNRS
• Université de Pau et des Pays de l’Adour, UPPA
• Technische Universität München, TUM
• IFP Energies Nouvelles, IFPEN
• Office National d'Etudes et de Recherches Aerospatiales, ONERA
• Deutsches Zentrum für Luft und Raumfahrt e.V. DLR
• Loughborough University, LU
• Università degli Studi di Firenze, UNIFI
• Centre de Recherche et de Formation avancée en calcul scientifique, CERFACS
• ARTTIC, ART
• Microturbo, MT
• Karlsruhe Institute of Technology, KIT

Contact details:
Dr Sebastian Roux
SNECMA
Site de Villaroche, Rond-Point René Ravaud - Réau
Tel: +33 1 60 59 71 69
E-mail: Sebastian.roux@snecma.fr
KIAI public website: www.kiai-project.