Conical Grid Plate Flame Stabilizers: Number and Size of Jet Shear Layers

Abstract

The influence of the number and size of the jet shear layers, at a constant total hole area, was investigated in a propane fuelled conical grid plate flame stabiliser. The combustion inefficiency, NOx and flame stability were determined for shear layer designs with 90, 8 and 4 holes. The total shear layer volume increased as the number of holes was reduced and combustion within these larger shear layers was responsible for the superior flame stability and combustion efficiency, but higher NOx emissions. Large shear layers and hence a small number of holes were necessary to achieve an adequate performance at a 400K inlet temperature, but at 600K the 90 hole system had the best combination of low NOx and combustion inefficiency. However, the 8 hole system had a performance close to the 90 hole system at 600K and better than it at 400K and was concluded to be the preferable design.