TS-74 Flame Structure of Very Lean Low NO_x Radial Swirl Stabilised High Intensity Combustion(Session C-8 NO_x Reduction 3)

概要

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Internal gas composition traverses were made of a lean low NO_x radial swirler natural gas combustor using radial inward fuel injection at the swirler outlet. The test conditions were simulated at atmospheric pressure at the flow condition of lean low NO_x gas turbine primary zones. The gas composition traverses were carried out at an isothermal flow Mach number of 0.03, which represents 60% of industrial gas turbine combustor airflow through the swirl primary zone. The gas composition contours showed that rapid fuel and air mixing achieved low NO_x, such that at the swirler outlet plane a near uniform mixture had been achieved. The traverses showed that at the 0.5 equivalence ratio primary zone with 600K inlet temperature, there were no local zones with flame temperatures above 1800K. Thus thermal NO_x had been nearly eliminated and the remaining NO_x was prompt. CFD predictions of the results were made with a NO_x post processing package that included both prompt and thermal NO_x, using joint PDFs to account for fluctuations in temperature and composition on NO_x. The agreement with the mean emissions was good, but the prediction of the flame profiles was not as good. This was mainly because the good fuel and air mixing close to the swirler was not well predicted, with more fuel predicted in the corner recirculation zone.
公益社団法人日本ガスタービン学会の論文
1999-11-14