Experimental Studies of Propellant Loading Parameters and Plasma Flow-Field Interactions

Propellant-plasma interaction has been attracting great interests among most researchers for application to an electrothermal-chemical (ETC) gun. Previous works have shown that propellant-plasma interaction can enhance burning rates due to increased surface erosion of propellants compared to that of conventional ignition. Plasma radiation and heat convection are the dominant mechanism of energy transfer based on both experimental data and numerical simulation. However, little literatures were reported about a detailed understanding of propellant loading parameters and the plasma flow-field distribution interactions, which is very important in deciding a successful propellant charge design in ETC guns. The pressure- time curves during interrupted-burning process of different propellants such as triethyeneglycol dinitrate (TEGN) and single- base propellants ignited by plasma were recorded by pressure sensor in interrupted-burning setup. Influence of loading parameters, including loading density, distance between propellants and plasma jet and propellant holding methods at the same selected location in plasma flow-field on plasma ignition performance of propellants was discussed based on experimental results. As the loading density of propellants increases, the porosity of the propellant bed becomes small. And the penetrating depth of plasma into propellant bed shortens. So the plasma energy attenuates rapidly and the ignition delay time of propellants becomes longer. The ignition delay time is longer when the distance between propellants and plasma jet increases. At the same selected location in plasma flow-field, different holding methods of propellant burning surface to plasma jet have less influence on the ignition, combustion process of propellants and the ignition delay time. The matching test results on propellant loading parameters and plasma flow-field distribution interaction play a major role in improving charge configurations at chosen plasma flow-field and- - understanding plasma-propellant interaction better.