Influence of Quenching Height and Air Distribution Ratio on Combustion Characteristics of RQL Combustor

Abstract

Based on the principle of the rich-burn/quench/lean-burn (RQL) technology, a low emission combustion chamber for gas turbine was designed. The effects of different heights of quenching structure and distribution ratios of the air flow on the flow field, temperature field, and pollutant formation characteristics of combustion chamber were studied under the premise of keeping the inlet parameters of combustion chamber unchanged. The results show that the height of quenching structure and the proportion of air distribution are important parameters affecting the combustion performance of the combustion chamber. With the decrease of the height of quenching structure, the NOx emission increases at the exit of the combustion chamber. The NOx emission from combustion chamber outlet first decreases and then increases with the decrease of the proportion of air mass flow from the main combustion hole to the fired air mass flow in oil-rich areas, and an optimal proportion of air mass flow makes the NOx minimum. The production of thermal NOx is directly related to the size of the region with a temperature higher than 1 900 K and the maximum gas temperature. The designed combustion chamber has a minimum NOx emission of less than 35 mg/m3 under the studied working conditions, which achieves the emission standard of a low pollution combustion chamber.

Keywords

• rich-burn/quench/lean-burn (rql) combustion chamber
• quenching structure
• air distribution
• nitrogen oxides (no<i>_x</i>)