Session: 04-33: Combustion Dynamics - Experiments III

Paper Number: 81769

81769 - Acoustic Flame Transfer Function Measurements in a Liquid Fueled High Pressure Aero-Engine Combustor 

This paper describes an experimental approach and study of thermo-acoustic flame transfer functions in a high-pressure liquid-fueled combustor. The presence of high background flame luminosity in high pressure sooty flame combustors precludes the application of any direct optical flame transfer function method. Instead, an acoustic method based on multi-microphones was employed to characterize the combustor acoustic pressure and velocity responses to acoustic forcing. A high-pressure siren device was employed to acoustically excite the combustor air flow over a broad range of frequencies from 10-1000Hz and modulate the combustor inlet amplitudes. The acoustic pressures measured from the microphones located upstream and downstream of the flame were employed in combination with an acoustic model of the combustor to extract flame transfer functions. The dynamic pressure sensors were located on waveguides of identical length and cross-section and each subject to same ambient temperature. Nonlinear behavior of the liquid fuel flame transfer function was studied by systematically varying the siren excitation pressure amplitudes. Good agreement was obtained between the projected pressure transfer functions at specific combustor locations calculated from downstream microphones and direct measurement. A parametric study of varying pressure and fuel-air-ratio was performed to study the impact of operating conditions on the measured liquid flame transfer function.

Presenting Author: Krishna Venkatesan GE Research

Presenting Author Biography: Dr. Venkatesan is a principal engineer in the Thermosciences organization at GE Research where he is involved in development and application of optical and laser-based combustion diagnostics for design of state-of-art combustion systems. Dr. Venkatesan’s ongoing activities involve application of laser-based diagnostics methods to reacting flows, acquisition of high-fidelity flow and combustion data for model validations, physics study and next generation combustor and propulsion system design. Dr. Venkatesan is the author of more than 30 peer reviewed articles and is an Associate fellow of the AIAA. Dr. Venkatesan is the recipient of the AIAA Best Paper Award in Propellants and Combustion in 2020. Prior to joining GE in 2008, Dr. Venkatesan was post-doctoral researcher at Purdue University where he received his Ph.D. in 2007.

Authors:

Krishna Venkatesan GE Research
Fei Han GE Research
Arin Cross GE Research