煤油简化化学反应机理在超燃数值模拟中的应用

Applications of reduced reaction mechanism for numerical calculations in supersonic combustion of kerosene fuel

针对一种适用于超声速燃烧流场数值模拟的新型26组元89反应简化燃烧反应机理,在RP-3航空煤油点火、定常/非定常燃烧流场数值模拟方面的效率与精度进行了研究。首先,对定常燃烧流场进行了典型算例数值模拟,得到了与试验数据相吻合的结果,分析表明该简化机理在计算精度方面具有明显优势。然后,针对气态煤油在超燃冲压发动机燃烧室内的非定常燃烧流场,将该简化机理与总包反应简化机理进行了对比,验证了该简化机理可以更准确地描述燃料燃烧过程中化学能的释放过程,并能够获得烯烃、炔烃等重要中间燃烧产物的空间分布规律,给出包括点火延迟等参数在内的更为全面的流场信息。研究结果表明,该新型燃烧反应简化机理在煤油燃料超声速燃烧流场的数值模拟方面具有较高的精度与效率,可以用于超燃冲压发动机内流燃烧流场的模拟与分析。

In this numerical study, the efficiency and accuracy of a new reduced mechanism （26species and 89 reactions） on the predictions of supersonic combustion in a model combustor are investigated, and the dynamic combustion process of RP-3 aviation kerosene in a model combustor is studied numerically. First, the predicted values of steady combustion are validated by the experimentally measured wall static press, and the results compared with quasi-global chemical reaction mechanism show that the reduced mechanism has better accuracy in combustion simulation. Furthermore, the unsteady combustion characteristics of a scramjet combustor with two different chemical reaction mechanisms are analyzed in detail. Predictions of the mass fractions of major species, such as alkanes, alkenes, and cycloalkanes species are presented and discussed. The calculations show that the reduced mechanism predicts the myriad details of the reacting flow field accurately, including the ignition delay and the process of heat release, which can improve the combustion simulation accuracy.