Numerical Investigation of the Combustion and Thermoacoustic Characteristics in an Annular Combustor with Hydrogen

Low emission combustion technology for gas turbine and aero-engine industrial has attracted more and more attention by the aeronautic community. Hydrogen fuel is believed being a promising alternative fuel for gas turbines and aero-engines in the next generation of propulsion system. In this work, a novel type of annular combustor with multi-point direct injection (MDI) burners for burning pure hydrogen is proposed for gas turbines and aero-engines. The MDI burner is featured with several multi-point injectors arranged in inclined direction, which forms a swirling flow to enhance the mixing process of hydrogen and air. Meanwhile, the MDI burners are beneficial for flame stability and preventing flashback. The flow structure, combustion process and NOx emission of a single MDI burner are numerically studied with hydrogen fuel under different air flow rate Qair and the equivalence ratio <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\phi$</tex>. Then, the cold flow and combustion characteristics of the annular combustor with 12 MDI burners are investigated by the steady RANS method to understand the flow structure, temperature field and NOx emission under different operation conditions. Furthermore, the thermoacoustic property of the annular combustor is investigated to obtain the acoustic modes, including the longitudinal modes and azimuthal modes.