Electrical ignition characteristics and combustion emission spectra of continuous-flow ADN-based liquid propellant

In this work, the ignition and combustion mechanism of continuous-flow ammonium dinitramide (ADN)-based liquid propellant under electric ignition mode is studied. The combustion process of ADN-based liquid propellants was divided into several stages, from ignition to complete combustion. The effects of ignition voltage and supply flow rate on energy consumption, temperature distribution and radical emission characteristics were studied, and the electrochemical decomposition mechanism of ADN-based liquid propellant was preliminarily explored. The research results demonstrated that increasing the ignition voltage can effectively enhance the initial heating power, significantly promote the decomposition of propellant and thereby accelerate its combustion process, while reducing the total electrical energy consumption. However, excessively high voltages can lead to combustion instability and necessitate matching with the supply flow rate. The emission of various radicals such as hydroxyl radical (OH*), imidogen radical (NH*), cyanogen radical (CN*), methylidyne radical (CH*), diatomic carbon radical (C₂*), and nitroxyl (HNO*) in the combustion flame of propellant was observed, and as the ignition voltage increased and the propellant supply flow rate rose, the wavelengths corresponding to the characteristic peaks of these radicals did not change, but their emission intensities increased.