Where does the highest formation of NOx occur in a Can-Annular combustor?

In a Can-Annular combustor, the highest formation of nitrogen oxides (NOx) occurs in the primary zone. This is primarily due to the conditions present in this zone, where the combustion process is most intense and temperatures are highest.

In the primary zone, the fuel mixes with air and ignites, creating a highly reactive environment where the formation of NOx can peak. The high temperatures promote the reaction between nitrogen and oxygen in the combustion air, leading to an increased production of NOx, particularly at peak combustion temperatures.

The cooling zone operates at lower temperatures and is designed to manage heat and prevent overheating, which would not favor NOx formation. The dilution zone is intended to mix cooler air with combustion gases to reduce temperatures and further minimize NOx production. The emission zone is typically where combustion gases exit, which has already seen a reduction in temperature and a decrease in reactive conditions that contribute to NOx formation.

Thus, within the combustion process of a Can-Annular combustor, the primary zone represents the crucial area for observing the highest NOx emissions due to the elevated temperatures and optimal conditions for chemical reactions that generate these pollutants.