Ignition And Combustion Studies Of NEPE Propellant Under Laser Irradiation

The ignition and combustion property of solid propellant is one of the main content in internal ballistic research, and it has a great significance for propulsion application and combustion mechanism. Experimental research of ignition and combustion properties of NEPE propellant has been done, and an analysis of factors which may be having influences on ignition delay time and temperature distribution of propellant surface has been performed in this paper.(1) In order to study the temperature effect on the properties of ignition and combustion of solid propellants, a conjugate heat transfer model of an enclosed square cavity with a plane heat source has been established firstly, then this 3-D flow and conjugate heat transfer model has been studied using FLUENT software. Simulation results show that three kinds of heating transfer, natural convection, heat conduction and radiation, exist in the enclosed square cavity. And the radiation takes a dominant position in the place where is near heating surface, and the natural convection dominated where is away from it.(2) An experimental system of CO2 laser irradiation ignition has been built, the optical system and the regulating system of environment parameters have been studied mainly when considering laser heat flux, environmental pressure and temperature, and a reasonable method to obtain experiment dates has been given.(3) Using high-speed camera and IR thermograph, the ignition and combustion process and the surface temperature distribution of NEPE propellant under laser irradiation were studied. The influences of laser heat flux, environmental pressure and initial temperature of NEPE propellant on the ignition delay time and the dynamic response of NEPE propellant after unloading laser were analyzed. Results show that the ignition delay time tends to decrease with the increase of laser heat flux, environmental pressure and initial temperature of NEPE propellant. But when the heat flux is less than a certain value, the ignition delay time decreases fast with the increase of laser heat flux, and varies little when the heat flux is greater than this value. At the same time, the influences that environmental pressure and propellant initial temperature have on the ignition delay time decrease with the increase of laser heat flux. Besides, laser irradiation on surface of NEPE propellant has an significant influence on temperature distribution of the propellant surface.