Numerical simulation of the influence of fuel allocation method on regional NOx production in a single sector combustor

Abstract

Aiming toward a single sector model of a central staged gas turbine combustor, this study developed a suitable numerical simulation calculation method coupled with a chemical reaction mechanism. A three-dimensional numerical simulation of the combustor was conducted on the basis of the validated numerical simulation method. The spatial production characteristics of NOx in each path of the combustor were analyzed by the plane integral method. The influence of payload and fuel allocation method on the NOx production of the combustor was also discussed. Results indicate the following. (1) Under 100% payload, the production of thermal NOx in the burnout zone contributed about 80% of NOx production due to the high temperature region, and the production of NOx in burnout zone (BOZ) contributed the highest, about 50% to the NOx fraction at the outlet of the combustor. The corner recirculation zone that contributed the least, which was about 10%. (2) As the payload increased from 30% to 100%, the NOx concentration at the outlet of the combustor increased exponentially by 75.58% and 156.85%. Thermal NOx was the most important NOx production path in each working condition and area, which contributed about 65–80% to the total production of NOx under different payloads. (3) The optimal fuel allocation method that suppressed NOx production and considered combustion performance was established. Under this method, the outlet NOx concentration was 13.03 ppm.