High temperature ignition is essential to the ignition and combustion of energetic metal fuels including the aluminum and magnesium particles protected by their oxides of high melting temperature. A plasma torch characterized by ultrahigh-temperature plasma plume fulfills such high-temperature ignition condition. A steam plasma igniter is newly designed and successfully validated with aluminum power ignition and combustion tests. The steam plasma rapidly stabilizes in both plasma and steam jet mode. Parametric investigation of the steam plasma jet is conducted in terms of the arc strength. A high-speed camera and oscilloscope method visualizes the discharge characteristics, and optical emission spectroscopy measures thermochemical properties of the plasma jet. Diatomic molecule OH fitting method, Boltzmann plot method, and short exposure capturing with an intensified charge coupled device record the axial distributions of the rotational gas temperature, excitation temperature, and OH radical distribution, respectively. The excitation temperature at the nozzle tip occurs near 5500 K, and the gas temperature 5400 K.
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