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A Study on Flame-Holding and Ignition of Hydrocarbon Fuel in Supersonic Flow

碳氢燃料在超音速流动中的保焰与点火研究

基本信息

批准号：
15560685
负责人：
WAKAI Kazunori
金额：
$ 2.24万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Hydrocarbon fuel is attractive for scramjet engine because of its high energy density. However, its low reactivity is pointed out as a large demerit. In order to use hydrocarbon fuel for a scramjet combustor, it is important to ensure ignition and flame-holding in a supersonic airflow. In this research, we use kerosene as a fuel and inject it into a scramjet combustor with a cavity, which is L in length and D in depth. The Mach number is 2 and the total temperature is 1800K-2400K. We also conduct numerical simulations as well as wind tunnel experiments. From the experimental result, it is found that there is a certain combination of L and D that leads to the maximum improvement of flame-holding performance. The numerical result shows that in a such case, large and complex vortex structure is generated in the cavity and prolong the residence time of the fuel in the combustor. On the other hand, it is predicted that the temperature in the cavity increases due to the decrease of the incoming flow. However, it is difficult to measure the temperature with intrusive method, such as a thermocouple. Hence, we adopt the two-band emission method instead with H2O as a target particle. We can measure the temperature in the cavity without disturbing the flow filed. The measured temperature was compared with the predicted one and they agree well. It is found that the well-designed cavity has good performance for flame-holding of hydrocarbon fuel in supersonic flow by prolonging the residence time and increasing the temperature.

碳氢燃料因其较高的能量密度而成为超燃冲压发动机的研究热点。然而，它的低反应性被指出是一个很大的缺点。为了将碳氢燃料用于超燃冲压发动机燃烧室，在超音速气流中确保点火和火焰保持是很重要的。在本研究中，我们以煤油为燃料，将煤油喷射到超燃冲压发动机燃烧室中，燃烧室的长度为L，深度为D。马赫数为2，总温为1800K-2400K。我们还进行了数值模拟和风洞实验。从实验结果可以看出，L和D存在一定的组合，使阻燃性能得到最大程度的改善。数值结果表明，在这种情况下，空腔内会产生大而复杂的旋涡结构，从而延长燃料在燃烧室中的停留时间。另一方面，由于进气量的减少，预测了空腔内的温度升高。然而，用热电偶等介入性方法测量温度是困难的。因此，我们采用以H2O为靶粒子的双能带发射方法。我们可以在不干扰流场的情况下测量空腔内的温度。将测得的温度与预测值进行了比较，两者吻合较好。结果表明，设计合理的空腔通过延长停留时间和提高温度，对超音速流动中的碳氢燃料具有良好的阻燃性能。