超燃冲压发动机燃烧室设计计算方法的研究

为寻找一种适当的计算超燃冲压发动机燃烧室性能的方法并评估现有模型的优劣,提出一维化学动力学模型,且通过几个算例验证了该模型的可靠性.为研究设计过程中的性能计算方法的适用性,针对一具体的燃烧室,采用目前通用的性能计算方法,即冲量分析法、一维化学动力学及二维化学动力学方法,计算得到燃烧室内各气动参数的分布曲线,并得到上述方法在超燃冲压发动机燃烧室设计过程中性能计算适用性的初步结论.计算结果表明:一维化学动力学方法与冲量分析法都能够考虑到摩擦、通道面积变化以及燃烧释热的影响因素,具有较好的适应性.对于冲量分析法,在考虑燃烧时,还需设定放热规律; 而一维化学动力学方法则可以利用化学反应模型,会自动计算释热规律,具有更大的独立性.和前两种模型相对比,二维化学动力学方法可以更细致地捕捉到流场中的一些细节,但此种模型需要较长的运算时间.对比这几个模型,各具有不同特点,在超燃冲压发动机的设计与性能计算过程中,需综合考虑上述区别,最充分地发挥各模型的优势.

Analysis of design calculation methods of scramjet combustion chamber

To find a proper way to calculate the performance of scramjet combustor and evaluate the present methods, one-dimensional chemical dynamics method was brought forward and tested with several cases. Calculation was carried out with three different methods: impulse analysis, one-dimensional chemical dynamics and two-dimensional chemical dynamics. Based on the comparison of aerodynamic parameters in combustion chamber obtained with the above methods, results show that one-dimensional chemical dynamics method and impulse analysis method can consider the influence of friction, the variation of tunnel cross area and the heat release, so the above two methods can be used to calculate the scramjet combustion chamber, which is always easy designed in configuration. As for impulse analysis, it is necessary to set the heat release discipline in chemical reaction related calculation, whereas it is unnecessary for one-dimensional chemical dynamics method, with the internal chemical reaction model obtaining the corresponding discipline. The two-dimensional chemical dynamics method can figure out the detailed information in the flow field, with taking up too much time. It is evident that different models have different advantages, so it is valuable to make the best use of each model in different calculation situation.