Study of the Effect of Shock Wave on Fuel Injection and Combustion

为了弄清低马赫数下超燃冲压发动机燃烧室内激波与燃烧相互作用的现象，对垂直壁面喷氢的保焰特性进行了实验和数值研究。得到了以下结果：1。当激波从注射缝的上游引入时，分离激波的位置向上游移动。因此，即使在较低的总温度和注射压力下，我们也能保持火焰。采用离散区域法对LU-SGS方法进行了改进，实现了想象中的并行化。数值结果与实验结果定性一致。由于大多数氢气停留在下游分离区并在那里发生反应，因此当当量比较小且氢气温度较低时，在下游分离区引入的入射激波比在注射缝上游引入的入射激波更有效。后一种情况下，由于复杂的湍流扩散，不能完全分析其持火过程。将二维燃料狭缝射流改为单圆形狭缝射流，可以在不发生热阻的情况下提高燃油喷射压力。同时，提出了一种将PTV与CFD相结合的超声速流动测量方法。

To clarify the phenomena of the interaction between shock wave and combustion in scramjet engine combustors at low Mach numbers, the fundermental research was performed experimentally and numerically flame-holding characteristics of hydrogen injected vertically to the wall surface. The following results ware obtaind :1.When the shock wave was introduced in the upstream of injection slit, the position of the detached shock wave moved to the upstream. As a result, we could hold the flame even at low total temperatures and injection pressures.2.The LU-SGS method was improved to be made in parallel imaginarily by a discrete region method.3.Numerical results were qualitatively consistent with experimental ones. Since the most hydrogen stayed in the downstream detached region and reacted there, the incident shock wave introduced in the downstream detached region was more effective compared with the case introduced in the upstream of the injection slit, when the equivalence retio was small and the hydrogen temperature was low. The flame-holding in the latter case, however, could not be analyzed completely because of complex turbulent diffusion.4.By changing from the two-dimensional fuel slit jet to a single circular slot jet, fuel injection pressure could be raised without thermal choke. Also, a new measurement method of supersonic flows was developed by linking PTV with CFD.