Control of Heat Release and NO Emissions in a Combustor Through Modulation of Transverse Air-Jets Onur Tuncer, Sumanta Acharya  , Jong Ho Uhm Department of Mechanical Engineering Louisiana State University, Baton Rouge, LA, USA Abstract: The effect of modulated air jets, introduced through the combustor shell, on the temperature distribution and nitric oxide emissions is investigated. Temperature and emissions measurements have been made at a number of forcing frequencies in the range of 100–850 Hz, blowing ratios in the range of 4–10 and equivalence ratios between 0.6 and 1.0. Open-loop flame response to forcing has also been acquired by recording pressure spectra. Results show that substan- tial reductions in nitric oxide emissions index (15–30%) can be obtained over a wide range of flow conditions with side-air jet forcing. In addition, forcing also alters the time averaged temperature field, with higher mean temperatures close to the dump plane, due to enhanced fuel-air mixing. The higher temperatures and volumetric heat release obtained with forcing can enable more compact com- bustor designs. The lower emissions are potentially linked to greater unsteadiness with forcing. Keywords: Emissions; Forced jet; Mixing; Spray combustion Received 28 February 2006; accepted 12 April 2007. This experimental study was supported by a grant from the ONR Propulsion program with Dr. Gabriel Roy as the program monitor, and by the Louisiana Board of Regents through the Clean Power and Energy Research Consortium (CPERC). This support is gratefully acknowledged. The help and support received from Mr. Jeffrey Willbanks in the various facets of the work is also acknowledged. Authors also would like to thank the editor and anonymous reviewers for their comments that helped to improve this article.  Address correspondence to acharya@me.lsu.edu Combust. Sci. and Tech., 179: 2255–2278, 2007 Copyright Q Taylor & Francis Group, LLC ISSN: 0010-2202 print/1563-521X online DOI: 10.1080/00102200701407911