超声速气流中的斜激波诱导自点火

在来流马赫数为2.5的条件下对氢气和乙烯燃料的斜激波诱导自点火过程进行了试验研究.采用纹影和高速摄影获得了自点火初始火核的形成和发展过程.试验考察了不同的来流总温、喷注条件、凹腔长度、斜激波强度等因素对自点火过程和点火边界的影响.研究结果表明:入射斜激波能够提高气流的局部参数起到强化自点火的作用.凹腔内形成的低速回流区有助于初始火核形成后的火核逆流传播,并起到防止初始火核因气流振荡而吹脱的稳定源作用.增加喷注压力、增加凹腔长度、提高来流总温有助于自点火的发生. 

Self-ignition in supersonic flow induced by oblique shock wave

Hydrogen and ethylene self-ignition induced by oblique shock wave were investigated experimentally with incoming Mach number of 2.5. The process of initial flame kernel generation and evolvement was observed with schlieren photography and high speed camera system. The effects of total incoming temperature, fuel injection conditions, cavity length and oblique shock wave intensity on the process of self-ignition and self-ignition boundary were studied experimentally. Results reveal that the performance of self-ignition can be improved by the enhanced effect of incident oblique shock wave on local flow-field. The low speed circulation zone created in cavity is beneficial to the upstream spreading of initial flame kernel, and acts as a function of flame-holding for preventing the blow-away of formed flame caused by flow oscillation. Self-ignition can be extended by increasing the injection pressure, cavity length and total incoming temperature.