The Structure Of The Combustion Chamber Combustion Ramjet Impact Studies

This thesis is aimed at the secondary combustion in Solid Ducted Rocket (SDR) after-burning chamber, according to the analysis of ignition and combustion of boron particle and the calculating results of fuel-rich propellant, a combustion model of fuel-rich gas was built. Based on RNG k-ε turbulence model, one step eddy-dissipation reaction model, and discrete random walk model, a numerical analysis model of the mix and combustion in the after-burning chamber is constructed. The three-dimensional reacting flow field of the ducted rocket was numerically studied by using FLUENT. The results show that the numerical analysis model can reasonably describe the mix and combustion in after-burning chamber, and it can be used for the numerical analysis of the secondary combustion in after-burning chamber.The pure-gas numerical calculating results show that enough length of after-burning chamber is necessay for the secondary combustion; and the mix and combustion can be intensified obviously by lengthening the after-burning chamber, but this influence would become weaker as the after-burning chamber is longer. Analysis shows that there is a proper design value for L~*/D, a bigger value is not useful for improving the secondary combustion efficiency. For this paper, this value for L~*/D is 3.75, and the fuel resorting time is about 2.91ms.The two-phase numerical calculating results show that, the secondary combustion exists in the head and the middle of after-burning chamber and the ramjet nozzle; in head of after-burning chamber and the ramjet nozzle, the length of after-burning chamber has little influence on the secondary combustion, but in the middle of the after-burning chamber, the combustion efficiency can be advanced by lengthening the after-burning chamber. But the effect can vary for different afterburning chamber structures.The study also shows that the ignition and combustion of boron particle lie on the resorting time and the environment temperature, and have no direct relationship with after-burning chamber's length. The resorting time can be delayed by lengthening the chamber, but the environment temperature is important to ignition.The results supply references for the design of the ducted rocket and the reseach of secondary combustion in after-burning chamber.