Chemiluminescence Measurements in a Combustor Using a 7-Point Lean Direct Injector Array Configuration for Gas Turbine Engine Applications

This paper reports results for a 7-point lean direct injector (LDI) array for a particular configuration. The LDI configuration in this study used a 60 degrees center pilot swirler and 52.5 degrees on the six outer swirlers. Chemiluminescence images of C2 and CH were collected at a frame rate of 25 Hz using an intensified CCD camera. Narrow bandwidth filters were coupled with the CCD camera in order to spectrally isolate C2 and CH signals. C2 was captured at 515 nm, and the CH signal was acquired at 430 nm. Six inlet conditions were considered in this study, all with the same inlet pressure, 75 psia, and same inlet temperature, 800 degcrees Fahrenheit. These conditions aimed to observe the effect of equivalence ratio, fuel staging, and reference velocity on C2 and CH emissions. Based on the chemiluminescence images, the changes in the inlet conditions was evident in both the pilot and outers. Additionally, the pilot (center injector element) appeared well isolated from the six outer elements under all test conditions.