Acoustic Control of Dilution-Air Mixing in a Gas Turbine Combustor

Abstract

A small combustor of normal design employing acoustic control of the dilution-air flows has been successfully tested up to “half-load” conditions. It has been shown that this technique can be used to control the exit plane temperature distribution; also the ability to trim the temperature profile has been convincingly demonstrated. The acoustic driver power requirements were minimal, indicating that driver power at “full-load” will not be excessive. The nature of the acoustically modulated dilution-air flows has been clearly established as that of a pulsating jet flow with superimposed toroidal vortices. The pressure loss of the unit and its combustion efficiency were insignificantly affected by the acoustic drive. The work contributes to the design of combustors such that a desired exit plane temperature distribution may be achieved.