Research On The Internal Ballistics Property Of Solid Fuel Ramjet

Because of the advantages of high specific impulse, high reliability and good security, the application foreground of solid fuel ramjet was extensive on supersonic missile and ramjet assisted projectile, but due to the complex internal combustion and flow,interior ballistics is difficult to accurately forecast, bring great difficulties to the design and test of the solid fuel ramjet. Carried on the thorough research on internal ballistic property of solid fuel ramjet by theoretical and numerical research, main did quantitative research on thrust, specific impulse, Combustion efficiency and Total pressure loss.Due to the SFRJ internal flow and combustion condition is more complex, increasing the difficulty of design, to some extent, restricting its application in engineering. It is necessary to establish the numerical simulation model, and in-depth analysis of the internal flow field patterns. Through the thermal equilibrium between gas and solid phase solution the solid fuel surface temperature, the solid fuel burning rate using the Arrhenius formula to calculate, this method need to determine the former factors and activation energy in Arrhenius formula, although complicating calculations, solve the contradictions of the fuel surface temperature. Based on this method, studying the inner flow field of SFRJ using HTPB as fuel. Compared with experimental data of Campbell Jr’s, it was presented that the numerical simulation model had high accuracy.The thrust mF equals the difference between nozzle exit jet and head on air. The definition of specific impulse is the thrust produced by a kilogram of fuel consumption per second. In order to establish predict calculation model on internal ballistic property of solid fuel ramjet,in-depthly researched the thrust and specific impulse according to its primary mission by theoretical and numerical method. Research results show that the theoretical formula of thrust is complex for more parameters,but the relative error is within 5% comparing to numerical result. Because the specific impulse depends on thrust and burning rate,so deduced out the average burning rate of solid fuel,and got an accurate result by putting it in the formula. The theoretical analysis process is rigorous and reveals the internal relations of each variable,moreover the numerical calculation model has high accuracy. So the theory formula of internal ballistic property has high applicability and credibility,it has a great reference value on preliminary design and simulation test of SFRJ.In order to have a calculation model of the combustion efficiency for solid fuel ramjet,the combustion efficiency model was built by theoretical analysis method,and initial expression was deduced, then numerically researched it in-depthly. Research results show that the numerical calculation model has high accuracy for the relative error within 3%,so numerical simulation can be used to validate the credibility of the research. it is exponential relationship between the combustion efficiency and inlet flow and chamber pressure and chamber length,the efficiency is special exponential relationship with chamber diameter for demarcation on D=2. The theoretical and numerical results present better fit after changing the operating mode, so the credibility is higher for combustion efficiency model and its fitting formula.In order to establish predict model on total pressure loss of combustion chamber for solid fuel ramjet,respectively established the calculation model for the three main parts of total pressure loss including the sudden enlargement flow loss,the added mass flow loss and the heat loss model by theoretical and numerical research,then derived the calculation formula for total pressure loss of combustion chamber and showed its validity by comparing calculation results with numerical simulation’s. Theoretical research results can be used to guiding SFRJ design and test research.