流-热化学耦合控制涡旋稳定微波等离子体反应器中压力依赖的CO₂转化：来自三维CFD模拟的见解
Flow-thermochemistry coupling governs pressure-dependent CO$_2$ conversion in vortex-stabilized microwave plasma reactors: Insights from three-dimensional CFD modeling
浏览论文内容
中文总结 AI 辅助
本研究开发三维CFD模型揭示涡旋稳定微波等离子体反应器中流-热化学耦合机制，明确CO₂转化的非单调压力依赖规律，解释不同压力下CO₂解离与CO复合的竞争及CO损失的关键作用。
中文摘要 AI 辅助
本研究针对工作压力范围为100-400 mbar的涡旋稳定微波CO₂等离子体反应器，开发了三维计算流体动力学（CFD）模型。该模型将实验约束的、基于发射的等离子体尺寸与体积热源分布，与多组分混合物中以热主导的有限速率重粒子化学相结合，采用SST k-ω模型描述湍流流动与输运。模型再现了测量得到的等离子体核心径向气体温度分布，以及CO₂转化的非单调压力依赖关系，包括在150 mbar时达到最大值、在400 mbar时显著下降的特征。涡旋驱动的再循环区使气体向上游再分布，湍流混合与冷却在反应器上部边界附近最强，但随压力升高其贡献降低。CO₂转化的压力依赖由CO₂解离与CO复合的竞争决定：CO₂直接解离反应在高温等离子体核心占主导，而O辅助转化反应在等离子体边缘及周围热区发挥作用。在150 mbar时，增强的CO₂解离伴随有限的CO损失，形成最高的转化效率；当压力升至400 mbar时，冷却减慢且三体碰撞更频繁，促进余辉区的CO复合，导致等离子体附近生成的CO中有超过60%在下游损失；此外，更高压力下因冷却速率降低，反应器上部区域还会发生额外的CO损失。
英文摘要
In this work, a three-dimensional computational fluid dynamics model is developed for a vortex-stabilized microwave CO$_2$ plasma reactor operating over the pressure range of 100-400 mbar. The model combines experimentally constrained, emission-based plasma sizes and volumetric heat-source distributions with thermally dominated finite-rate heavy-particle chemistry for a multi-component mixture. Turbulent flow and transport are described using the SST k-omega model. The model reproduces the measured radial gas-temperature profiles in the plasma core and the non-monotonic pressure dependence of CO$_2$ conversion, including a maximum at 150 mbar and a pronounced decrease at 400 mbar. A vortex-driven recirculation region redistributes gas upstream. Turbulent mixing and cooling are strongest near the upper reactor boundary, but their contribution decreases as pressure increases. The pressure dependence of conversion is determined by the competition between CO$_2$ dissociation and CO recombination. CO$_2$ direct dissociation reaction dominates in the high-temperature plasma core, whereas O-assisted conversion reaction contributes near the plasma edges and in the surrounding hot region. At 150 mbar, enhanced CO$_2$ dissociation is accompanied by limited CO loss, resulting in the highest conversion. With pressure increasing to 400 mbar, slower cooling and more frequent three-body collisions promote CO recombination in the afterglow, causing more than 60% of the CO formed near the plasma to be lost downstream. Moreover, additional CO loss occurs in the upper region of the reactor at higher pressures because of the reduced cooling rate.
