Study on the spray combustion characteristics of a high intensity swirl combustor. (2nd report NOx reduction effects in staged combustion)

Abstract

NOx reduction effects by two-stage spray combustion in a high intensity swirl combustor have been investigated using kerosene with a pyridine content of 0-1.7%. The secondary air was radially injected into the combustion chamber through a multiholed tube, which was axially inserted from the rear side of a cylindrical combustor. Experiments have been carried out varying a secondary air injection point, a primary to secondary air ratio, pyridine content and a fuel flow rate. The main experimental results are as follows: (1) by the effective mixing of a fine fuel spray with an air flow of a large swirl degree in the primary combustion zone and by suitable supply of the secondary air, combustion of low NOx emission can be realized even in a high intensity combustor. (2) The injection of the secondary air at a point where the primary combustion is almost completed is effective for reducing NOx emission. (3) A primary to secondary air ratio for low NOx emission has a tendency to increase with a decrease of combustion intensity.