Trends in Research and Development of Combustor Applying the Principle of Micromix

Energy demand and environmental pollution control are challenging issues in the field of gas turbine applications, with the aim of achieving zero carbon and low NOx emissions from combustion gases. In this context, hydrogen fuel is anticipated as a future energy source capable of replacing carbon-based fuels. However, hydrogen presents technological challenges related to safety issues such as flashback and autoignition. Additionally, there is a need to address issues of increased NOx emissions due to high adiabatic flame temperatures. To overcome these challenges, research is underway to develop combustion systems, particularly in the form of micromix or micro-mixer configurations. The micromix combustion system, which uses small nozzles and flames, has been evaluated as one of the most suitable combustors for hydrogen and hydrogen-blended fuels by preventing flashback and reducing NOx emissions. This paper introduces the effect of various geometric factors, such as fuel injection shapes, fuel inlet and nozzle numbers, and internal configurations, on the optimal design and combustion instability of micromix combustion systems. The characteristics of combustion systems developed by research institutions and companies are also analyzed. The paper concludes with a discussion on the applicability of micromix combustion systems to hydrogen combustion applications.