Research On Characteristic Of Heat Transfer And Ablation Of Insulation In The Solid Rocket Ramjet Chamber

Because of the advantages such as simple structure, convenient usage, high specific impulse and reliable working performance of solid rocket ramjet, it will have a wide application for the solid rocket ramjet. During the working time, the oxygen-poor fuel gas from the generator and the air from the inlet mixed with each other first, and then combusted again in the second combustion chamber, so the inner wall of second combustion chamber is surrounded by the fuel gas with high pressure and high temperature. There is strong heat transfer between the fuel gas and the inner wall. And it is oxygen-rich in the inner environment of chamber. Because of the use of the high energy propellant and the high strength material, along with the more heat transfer and the reduction of ramjet shell, the hot strength will be more serious. The unfitted thermal protection system will result in the burn through of the chamber and the failure of the ramjet. So, it must be pay more attention. Therefore, it is very important and necessary to specially research the heat transfer and ablation properties of insulation in ramjet chamber. Aiming at above problems, in this thesis, heat transfer and ablation properties of insulation in ramjet chamber are studied by using the numerical simulation method and tests. The main researches are as follows:(1) Based on k-εtwo equations, the physical model of pure gas phase flow fields with reacting in the ramjet chamber and the relevant boundary conditions and numerical method are given. By the numerical simulation, the flow field structures and the fuel gas properties such as temperature velocity and pressure in the ramjet chamber are obtained. According to the fuel gas properties, the heat transfer coefficient between the fuel gas and the inner wall of chamber can be computed. These data is helpful for the researching on the numerical simulation of heat transfer and ablation of insulation as the heat load.(2) Establishing the physical model of the heat transfer and ablation of insulation in the combustion chamber, the corresponding boundary conditions are proposed and the numerical simulation is carried out. The heat transfer with pyrolysis and ablation under oxygen-rich environment are researched. The temperature contour in the insulation and the ablation rate can be obtained by the numerical simulation. The main influence factors of the material on the heat transfer and ablation and the relations between those factors are analyzed.(3) The thermal gravity test and gas generator test and connected pipe test for ramjet is used for the heat transfer and ablation test of insulation in chamber. The heat transfer and abalation mechanism are obtained. The methods of temperature measurring and temperature amending are presented. During the working time of the ramjet, the back-face temperature of the thermal protection material is measured. After test, the ablation rate of insulation is measured too and the scanning electron microscope of samples was investigated. So all of them can provide effective test data for the establishment and computation and validating of heat transfer and ablation of the chamber insulation.This paper researches the heat transfer and ablation properties of the insulation, and establishes the numerical and physical model of insulation, and forms the compute program of the insulation heat transfer and ablation model. And the influence on the heat transfer and ablation by the properties of combustion gas is obtained. These results are significant to the design and application of insulation in ramjet combustion chamber, and supply a fundament to the theory research of heat transfer and ablation mechanism of this kind of insulation.