Characterization of the reactive flow field dynamics in a gas turbine injector using high frequency PIV

TL;DR

This study employs high-frequency PIV to analyze the unsteady turbulent flow in a gas turbine combustor, revealing periodic large coherent structures linked to combustion instability.

Contribution

It introduces a 12 kHz high-frequency PIV system for detailed temporal analysis of reactive flow fields in gas turbine burners.

Findings

Large coherent structures periodically appear in the flow.

The frequency of these structures matches the quarter wave mode of the chamber.

This may explain the coupling mechanism behind combustion instability.

Abstract

The present work details the analysis of the aerodynamics of an experimental swirl stabilized burner representative of gas turbine combustors. This analysis is carried out using High Frequency PIV (HFPIV) measurements in a reactive situation. While this information is usually available at a rather low rate, temporally resolved PIV measurements are necessary to better understand highly turbulent swirled flows, which are unsteady by nature. Thanks to recent technical improvements, a PIV system working at 12 kHz has been developed to study this experimental combustor flow field. Statistical quantities of the burner are first obtained and analyzed, and the measurement quality is checked, then a temporal analysis of the velocity field is carried out, indicating that large coherent structures periodically appear in the combustion chamber. The frequency of these structures is very close to the quarter wave mode of the chamber, giving a possible explanation for combustion instability coupling.