KIAI - Knowledge for ignition, acoustics and instabilities
Overview
Background & policy context:
Air traffic is growing. Aircraft pollutant emissions need to be reduced. Until 2020, ACARE's Societal Research Agenda (SRA) demands a reduction of 50% CO2 emissions per km and per passenger and 80% less NOx emissions.
Moreover, studies show that there are no methodologies available for the European aero engine industry to predict the unsteady behaviour of low NOx combustors. In order to be able to set up the development of low NOx technologies, the KIAI project will deliver reliable unstationary Computational Fluid Dynamic ("CFD") tools which will allow a deep comprehension of unsteady phenomena.
Objectives:
The objective of the KIAI project is to provide reliable methodologies to predict: (i) the stability of industrial low NOx combustors, and (ii) 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 the 80% NOx emissions reduction (which is required for introduction into service before 2020) combined with the necessary reliability, safety and economical viability.
Methodology:
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 analysis therefore focusses on a better understanding and prediction of these unsteady phenomena, to:
- predict the coupling between the acoustics and the flame;
- determine the acoustic boundary conditions of multiperforated plates surrounding the combustion chamber;
- account for non-premixed spray flows in the combustion process;
- explore aerodynamic unsteadiness in strutted pre-diffusers adapted to high mass flow injectors and develop a liquid film break-up model for an injector;
- evaluate the sensitivity of LES predictions to small technological variations of geometry.
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