EAGER: Design and Fabrication of a Novel Micro-Reactor for Molecular Sampling of Combustion

高温气相化学，如负责为发动机提供动力和从发电厂向家庭供电的化学物质，是复杂的。但了解这些化学过程对于提高能源效率和减少污染至关重要。很少有实验能够全面了解复杂反应体系中发生的化学情况，因为形成的许多关键分子物种都是不稳定的，寿命非常短。这项工作的重点是开发新型的微反应器，它可以探测微秒量级的化学，以直接测量气相反应体系的基础化学。当与其他诊断相结合时，这些微型反应堆将提供所发生化学过程的几乎完整的化学图像。如果成功，这些被提议的微反应器将成为一个有价值的研究工具，将显著提高现场测量气相反应化学产物的能力，导致更准确的动力学模型，从发动机设计到空气质量建模具有广泛的应用。本研究工作的目的是设计和制造一种用于燃烧和气相反应流动的先进化学诊断的新型微反应器。虽然以前使用微型反应器来研究热解(热分解)反应，但由于基材碳化硅(SiCd)与氧气的反应性质以及反应器中不确定的压力和温度条件，这些反应器的实验能力受到限制。为了直接解决这些问题，将使用计算分析重新设计反应器的几何结构，以在反应器内产生稳定的热力学流体性质，从而准确确定反应温度和压力。然后，这些反应堆将使用3D打印、铸造和微钻孔方法相结合的方法来制造。计划建造两套反应堆：一套将由碳化硅制成，用于与现有的热解反应堆进行比较；另一套将由非反应性材料(如石英或蓝宝石)制成，用于燃料氧化研究。这些反应堆的性能表征将通过一系列实验来完成，这些实验探索燃料在反应环境中的温度和压力行为。这一强大的新仪器有可能帮助解开仍然悬而未决的问题，如煤烟是如何形成和摧毁的，点火的主要反应途径是什么，污染物如何与高层大气中的臭氧相互作用。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

High-temperature gas-phase chemistry, such as the chemistry responsible for powering engines and supplying electricity from power plants to homes, is complicated. But it is critical to understand these chemical processes to make advancements in energy efficiency and pollution reduction. Few experiments exist that can get a full chemical picture of the chemistry occurring in complex reacting systems, since many of the critical molecular species formed are unstable with very short lifetimes. This work focuses on the development of new micro-reactors that can probe the chemistry on the order of microseconds to directly measure the fundamental chemistry of gas-phase reactive systems. When coupled with other diagnostics, these micro-reactors will give a nearly full chemical picture of the chemistry that occurs. If successful, these proposed micro-reactors will be a valuable research tool that will significantly enhance the ability of the field to measure the chemical products of gas-phase reactions, leading to more accurate kinetic models with wide ranging applications from engine design to air quality modeling.The objective of this proposed work is to design and fabricate a novel micro-reactor for advanced chemical diagnostics for combustion and gas-phase reactive flows. While micro-reactors have been used to study pyrolysis (thermal decomposition) reactions previously, these reactors are limited in their experimental capabilities due to the reactive nature of the base material, silicon carbide (SiC) with oxygen and uncertain pressure and temperature conditions in the reactor. To directly address these issues, computational analysis will be employed to redesign the geometry of the reactor to produce stable thermodynamic fluid properties within the reactor, leading to accurate determination of reaction temperature and pressure. Then, these reactors will be fabricated using a combination of 3-D printing, casting, and micro-drilling methods. Two sets of reactors are planned: one set will be made of SiC for comparison to existing pyrolysis reactors and a second set will be made of non-reactive materials, such as quartz or sapphire, for fuel oxidation study. Performance characterization of these reactors will be completed through a series of experiments that probe the temperature and pressure behavior of fuels in a reactive environment. This powerful new instrument has the potential to help unravel still unanswered questions such as how soot is formed and destroyed, what are the dominant reaction paths for ignition, and how do pollutants interact with ozone in the upper atmosphere.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.