Experimental Two-Phase Flow Analysis Inside a Laboratory Scale Jet-Engine Combustion Chamber Using Particle Image Velocimetry

Abstract

The characterization of the two-phase kerosene/air flow near the nozzle of an aero-engine combustor is important in order to understand the combustion characteristics of the burner. Typically, particle image velocimetry (PIV) or laser Doppler velocimetry is used to measure velocities inside aero-engine combustors. However, these measurement techniques rely on tracer particles to visualize the flow field and are usually only able to measure the velocity field of one phase at a time. In the case of PIV measurements, both the flow tracers and the kerosene droplets scatter the laser light, and thus appear on the PIV recordings. Depending on droplet size and flow velocity, these kerosene droplets do not necessarily follow the airflow leading to errors in the derived velocity field. This work presents a method on how to separate kerosene droplets from flow tracers depending on their optical characteristics in the PIV recording. This phase separation enables the independent measurement of the flow fields of both the gaseous and liquid phase at the same time as well as the instantaneous slip velocity between droplets and gaseous flow using a standard PIV setup. The method is demonstrated on a laboratory scale aero-engine combustor operated at atmospheric conditions. The obtained results show that in the setup under investigation, gaseous and liquid phase can have significantly different flow fields with kerosene droplets moving in the opposite direction of the recirculating airflow.