Numerical Investigation of the Plasma-Assisted MILD Combustion of a CH4/H2 Fuel Blend Under Various Working Conditions

Abstract

The effects of plasma injection upon MILD combustion of a mixture of methane and hydrogen are investigated numerically. The injected plasma includes the flow of a highly air-diluted methane including C2H2, C2H4, C2H6, CH, CH2, CH3, CO, and CO2. The results show that amongst all the constitutes of plasma, CH3 is the most effective in improving the characteristics of MILD combustion. Injection of this radical leads to the occurrence of reactions at a closer distance to the burner inlet and thus provides longer time for completion of combustion. Further, mass fractions of OH, CH2O, and HCO are considerably affected by the injections of CH3, indicating structural modifications of the reacting flow. Importantly, as Reynolds number of the plasma flow increases, the volume and width of the flame decrease, while the formations of prompt and thermal NOx are intensified. However, injection of CH3, as plasma, reduces the emission of thermal NOx.

On the Response of Ultralean Combustion of CH4/H2 Blends in a Porous Burner to Fluctuations in Fuel Flow—an Experimental Investigation

“…Nonetheless, this still poses a substantial concern, hence there exist active plans for decarbonization of gas grids. , Injection of hydrogen to natural gas pipelines has been identified as a practical approach to reduce carbon emissions. , As a result, in recent years, there has been a surge of research interest in the combustion of hydrogen and methane mixtures, for example, refs , . Although these studies , have provided a wealth of insights into the problem, they are chiefly focused on lean premixed and partially premixed flames . This makes them pertinent to high-temperature applications typically more than 1500 K. There are, however, an increasing number of applications in which high temperatures are not needed, and generation of heat at moderate temperatures is preferred .…”