Simplified Reaction Mechanisms for the Oxidation of Jet Fuel

Jet fuel is a complex mixture comprising thousands of components, which poses challenges for conducting kinetic simulations on its oxidation process. To address this issue, the HyChem (hybrid chemistry) approach has recently been proposed as an effective method for modeling the oxidation of real multicomponent fuels. Nevertheless, the simplest HyChem approach still involves 31 species and more than 100 reactions, presenting a significant challenge for computational fluid dynamics (CFD) simulations of real multicomponent fuels. In order to enhance the computational efficiency and affordability of numerical simulations for reactive flow, this study developed three simplified mechanisms, namely S66 (28 species and 66 reactions), S8 (12 species and 8 reactions), and S2 (5 species and 2 reactions), which depict the high-temperature (<i>T</i> = 1000～1470 K), high-pressure (<i>P</i> &gt; 1.0 atm), and fuel-lean (<i>φ</i> &lt; 0.7) oxidation of real multicomponent jet fuels inspired by the HyChem methodology and single-step overall reaction. The accuracy of the mechanisms was validated using experimental data, including ignition delay times and laminar flame speed from the literature. Notably, the CPU time required for the simplest HyChem model is longer than 20 times that of the S2 mechanism under identical conditions in the CFD simulation example. This is due to the highly simplified approach of the S2 mechanism. Consequently, the S2 mechanism is expected to be applicable in combustion kinetic simulations in complex environments such as combustion chambers because of its high computational efficiency and relative accuracy.喷气燃料（jet fuel）是包含数千种组分的复杂混合物，其氧化过程的动力学模拟因此面临诸多挑战。为解决这一难题，HyChem方法（hybrid chemistry）近期被提出，可有效模拟真实多组分燃料的氧化过程。然而，即便最简版HyChem方法仍涉及31种组分与百余步反应，这对真实多组分燃料的计算流体动力学（computational fluid dynamics, CFD）模拟仍构成显著挑战。为提升反应流动数值模拟的计算效率与经济可负担性，本研究基于HyChem方法与单步总反应框架，开发了三款简化燃烧机理：S66（含28种组分、66步反应）、S8（含12种组分、8步反应）以及S2（含5种组分、2步反应），可用于模拟真实多组分喷气燃料在高温（T=1000～1470 K）、高压（P>1.0 atm）及贫燃料（φ<0.7）条件下的氧化过程。上述机理的精度通过公开文献中的实验数据得以验证，实验数据涵盖点火延迟时间与层流火焰速度。值得注意的是，在本次CFD模拟算例的相同工况下，最简版HyChem模型所需的CPU时长是S2机理的20倍以上，这得益于S2机理的高度简化特性。因此，凭借极高的计算效率与相对可靠的精度，S2机理有望应用于燃烧室等复杂场景中的燃烧动力学模拟。