FWF - Luftzerstäubungs-Regelungskonzept - Evaluating active control strategies for airblast-injection

Project: Research project

Project Details

Description

This research project focuses on unsteady two-phase flow behaviour at high pressure and temperature levels, and is
ground-research oriented. The aimed field of application is the stability of airblast atomisation, which is the
common injection device used in modern aeroengines. Collateral fields are for instance liquid-fueled rocket engine
stability, internal combustion engine injection, drying spray process control (pharmaceutical + agri-food industry),
and coating quality control (metallurgy).
New designs for performant and sustainable gas turbine combustors include low-NOx injection technologies, such
as lean-premixed-prevaporised (LPP) burners. These systems that operate at high pressure ratios and near the
blow-out limit are known to be sensitive to self-induced combustion oscillations. If "heavy" combustion control
systems are already applied with success on stationary gas turbines, their transfer to aeroengines is not trivial.
There is still a lack of understanding on the physics of unsteady multiphase flow that prevents to master the
steadiness of combustion.
Actuating the injection is the most feasible solution to damp combustion instability. In this study, we want to
rate different airblast actuation strategies required to stabilise the equivalence ratio of the mixture at the
level of the flame, or to phase-control this mixture.
We propose to act as follows:
The approach of the study will be numerical, using an Euler-Lagrange scheme for the simulation of a twophase
flow on a 3D computational domain
A set of basic experiments will be required to validate the numerical models, as well as measure finely the
effect of a specific actuation, for precise boundary condition input
Studied parameters will be the effect of pulsed air only, pulsed liquid only, and simultaneously pulsed air and
liquid (phase-shifted) on the mixture in the far field
Specific numerical development will concern the implementation of unsteady boundary conditions,
introduction of the liquid phase, interaction air-particle, simultaneous particle transport and evaporation
under unsteady conditions
Specific experimental development regards the selection or development of actuators, their control, their
testing, and the development of synchronised measurement techniques
Works previously realised by the applicant at ONERA and DLR will serve as extra data banks for our
parametric analysis (airblast atomisation and evaporation fully characterised for specific geometries, at high
pressure and temperature conditions, under steady and unsteady conditions)
At the end of this project, the defined guidelines for the realisation of an ad-hoc airblast atomiser (order of
magnitude of the liquid/air flow actuation and phase-control issues) will be the input of a future project,
where these results will incorporate combustion, be experimentally tested and validated
This project requires two PhD's positions over three years (simulation and experiments) plus one PhD over one and
a half year (fast control technology). The study will take place at the Combustion Unit, Institute for Thermal
Turbomachinery and Machine Dynamics, at the Graz University of Technology.
StatusFinished
Effective start/end date1/07/0830/06/11