Characterisation of an air-blast injection device with forced periodic entries

Abstract

This research project is related to the control of combustion instability occurring intermittently in aeroengines. The unsteadiness of the flow in the combustion chamber is conducted by a particular instability called Combustion-Driven Oscillations (CDO). The experimental set-up at the ONERA Centre de Toulouse was designed in order to simulate the modulation exerted by CDO on the injection process. By pulsating both gas and liquid entries with specific actuators it is possible to reproduce the effect of the acoustic pressure on the resulting spray. This paper presents the first measurements performed on the free jet under non reacting and atmospheric conditions. The aim is to acquire a data set of the two-phase flow characteristics (pressure, temperature, fuel particle size and local spray density) along one period of pulsation. These experimental data are used to understand the periodic flow behaviour. They are also required for a further validation of a numerical code. This project is done in collaboration with SNECMA Moteurs and supported by the DGA.