10. Combustion and Reacting Flows

Micro-mixing combustion technology can inhibit the hydrogen combustion instability and flashback due to a very short residence time of reactants in the flame region of the micro-flames. This makes micro-mix technology a prominent hydrogen-rich gas turbine combustion technology. This study looks into the potential of micro-mix combustion technology for achieving low emission or low NOx hydrogen gas turbine. This study first focused on developing a detailed chemical kinetic mechanism which helped in describing the combustion behavior of H2 and also H2 mixed with CH4. This included the development of a reaction mechanism focusing on NOx formation rates. Chemkin was employed and the results like burning velocity and NOx formation rates showed high accuracy throughout the range of equivalence ratios (0.8-1.2) when compared to experimental results from the literature. Second part of the study focused on investigating the influence of geometrical variations and their consequences in terms of mixing behaviour over flame characteristics, which involved studying parameters such as inlet channel diameter and mixing channel diameter. The study result revealed that with increase in the inlet channel diameter, mixing zone moves near to wall. With the extension of premixed length, always there was a decrease in vorticity which causes mixing efficiency drop. The results indicate that the micro-mixing hydrogen combustion has a lot of potential to improve it further toward very low NOx emission. In view of these results, the efficiency towards zero or close to zero emission can be optimised by implementation into micro-mixing burners which should find their way successfully in industrial gas turbine applications.

Prof.

Shouyin Yang

Corresponding author