Session: 04-22: Combustion Dynamics - Experiments I

Paper Number: 81590

81590 - Experimental Investigation of Combustion Dynamics in a High-Pressure Liquid-Fueled Swirl Combustor 

This paper presents advanced diagnostic measurements in a high-pressure, liquid spray, RQL-style combustor rig. The combustor has a swirler with two separate fuel circuits, namely the primary (which has a pressure atomizer nozzle) and secondary (which has an air blast type nozzle) circuits. The measurements include acoustic and high-speed (10 kHz) stereoscopic particle image velocimetry (SPIV) measurements. The PIV measurement was performed on radial-azimuthal planes at different axial positions. The data were acquired during two dynamical regimes – combustion noise, where there is an absence of large amplitude oscillations during the unsteady combustion process, and intermittency, where there are intermittent bursts of high amplitude oscillations that appear in a near-random fashion amidst regions of aperiodic low amplitude fluctuations. This dynamic transition from combustion noise to combustion intermittency is investigated experimentally by systematically varying the fuel equivalence ratio and primary-secondary fuel splits. Typical measures such as the amplitude of oscillations cannot serve as a measure of change in the dynamics from combustion noise to intermittency due to the presence of turbulent noise. Hence, recurrence plots and complex networks are used to understand the differences in the combustor acoustics and velocity data during the two different regimes. We observe that the combustor transitions from stable operation to intermittency when the equivalence ratio is increased for a given primary fuel flow rate and conversely, when the percentage secondary fuel flow rate is increased for a given equivalence ratio.

Presenting Author: Aravind Chandh Georgia Institute of technology

Presenting Author Biography: Aravind Chandh is a Ph.D. student at the Ben T Zinn Combustion Lab. He currently works on high pressure, swirl stabilized, liquid fuel combustor. His research experience includes mapping thermo-acoustic instabilities, studying dynamics of film cooling, Infrared imaging, high-speed laser diagnostics, and combustor system design.

Authors:

Aravind Chandh Georgia Institute of technology
Subodh Adhikari Georgia Institute of Technology
David Wu Georgia Institute of Technology
Randal Mckinney Georgia Institute of Technology
Benjamin Emerson Georgia Institute of Technology
Qingguo Zhang Pratt & Whitney
Dibesh Joshi Pratt & Whitney
Baris Sen Pratt & Whitney
Dustin Davis Pratt & Whitney