乙烯简化化学动力学模型在HIFiRE燃烧室计算中的应用

为评估化学反应动力学模型对超燃冲压发动机计算结果的影响,首先利用基于"准稳态"假设方法建立了复杂化学反应动力学模型简化软件包(SPARCK),从详细模型出发得到了一个包含20组分16步总包反应的乙烯简化动力学模型.然后采用该简化模型和Princeton大学的简化模型对乙烯点火延迟时间进行了计算,对比显示两个简化模型计算结果基本一致,与实验测量结果均吻合较好,都能准确反映乙烯点火特性.但对HIFiRE燃烧室直连式实验的数值模拟结果显示两个模型计算得到的燃烧流场静温分布差别较大,内流道推力性能相差近12%.相比于Princeton大学的简化模型,SPARCK软件得到的简化模型计算的壁面压力分布与实验结果吻合更好,能够准确描述燃烧室流场现象.

Application of reduced chemical kinetic model for ethylene combustion in combustor calculation of HIFiRE

In order to assess the influence of chemical kinetic models on the computational results of scramjet, a software package for reduced chemical kinetics (SPARCK) was used based on quasi-stationary state approximation and specifically developed for chemical reaction kinetics reduction, and a reduced chemical kinetic model with 20 species and 16 global reactions was achieved by reducing the detailed chemical kinetic model for ethylene combustion. Then, the ignition delay time of ethylene was calculated with the reduced model and another reduced model generated by Princeton University. The computational results showed two reduced models almost had the same ignition delay time, and achieved a good agreement with experimental results. Both models can describe the ignition characteristic of ethylene. The Hypersonic International Flight Research Experimentation (HIFiRE) direct-connect test was numerically simulated using two reduced chemical kinetic models. The computational results showed two reduced chemical kinetic models had big difference in the static temperature of combustor, with nearly 12% relative error in the flowpath thrust. The reduced model, obtained by SPARCK, showed better agreement with experimental data for wall pressure distribution, as compared with the Princeton University model, and could simulate accurately combustion phenomena in scramjet combustor.