Regimes of plasma-assisted ignition of turbulent hydrocarbon mixtures

实验表明，一类特殊的等离子体被称为非热等离子体可以点燃碳氢化合物/空气混合物在非常贫燃料的条件下，传统的点火方法已经失败。这些非热等离子体通过高活性分子起作用，这些分子以低能量输入刺激燃烧过程。在这个项目中，我们将开发和实现一个鲁棒的和精确的预测模型，该模型可用于优化燃烧装置中湍流的等离子体辅助点火。如果成功的话，开发的模型具有巨大的潜力，可以减少燃烧产生的排放，提高热循环效率，对能源安全和环境产生积极的影响。该项目的特点是旨在加强本科生STEM教育在UT奥斯汀，并有可能在高中（G9-12）在整个项目完成后，美国采用的活动。尽管在改善能源转换过程的技术承诺，等离子体放电的相互作用，耦合等离子体和燃烧化学动力学，湍流传输缺乏系统的了解。为了在实际设备中实现等离子体辅助点火（派），实现低排放和高效率的能量转换技术，需要了解这些情况。派事件的结果取决于能量和等离子体产生的自由基从点火内核中的运输与加速化学动力学和热释放之间的竞争。在这个项目中，我们将确定无量纲参数，管理派的湍流反应混合物，并利用大规模并行和大规模模拟定义状态图。采用的高保真物理模型确保没有调用闭包。在我们的方法中考虑的流动配置是一个典型的均匀各向同性湍流，从而湍流传输率和所有其他相关的规模可以仔细控制。将考虑等离子体放电的时间和空间尺度，湍流，化学动力学，以及热量和质量的分子扩散率。模拟数据将使用强大的新的数学技术进行分析，这些技术量化了瞬态点火事件期间化学反应和局部瞬时运输的竞争。我们的方法的一个重要方面是，模拟将密切反映派实验在湍流燃烧容器中进行的平行由我们的合作者，提供了独特的机会，直接compared.This奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的智力价值和更广泛的影响审查标准。

Experiments indicate that a special class of plasmas known as non-thermal plasmas can ignite hydrocarbon/air mixtures under extremely fuel-lean condition where conventional ignition approaches have failed. These non-thermal plasmas act through highly reactive molecules that stimulate the combustion process with low energy input. In this project, we will develop and implement a robust and accurate predictive model that can be used to optimize the plasma- assisted ignition of turbulent flows in combustion devices. If successful, the model developed holds enormous potential to reduce combustion-generated emissions and improve thermal cycle efficiency with positive outcomes for energy security and the environment. The project features activities that seek to enhance undergraduate STEM education at UT Austin and are likely to be adopted in high schools (G9-12) throughout the United States upon completion of the project.Despite the technological promise with regard to improving energy conversion processes, a systematic understanding of the interaction of plasma discharges, coupled plasma and combustion chemical kinetics, and turbulent transport is lacking. Such understanding is required in order to implement plasma-assisted ignition (PAI) in practical devices towards low-emission and high-efficiency energy-conversion technology. The outcome of a PAI event depends on the competition between transport of energy and plasma-generated radicals out of the igniting kernel and accelerating chemical kinetics and heat release. In this project, we will identify the non-dimensional parameters that govern PAI of turbulent reactive mixtures and define regime diagrams by leveraging massively parallel and large-scale simulations. The high-fidelity physical models employed ensure that no closures are invoked. The flow configuration considered in our approach is a canonical homogeneous isotropic turbulent flow whereby the rates of turbulent transport and all other relevant scales may be carefully controlled. Consideration will be given to temporal and spatial scales of plasma discharges, turbulent flow, chemical kinetics, and rates of molecular diffusion of heat and mass. Data from simulations will be analyzed using powerful new mathematical techniques that quantify the competition of chemical reactions and transport locally and instantaneously during transient ignition events. An important aspect of our approach is that simulations will closely mirror PAI experiments in a turbulent combustion vessel conducted in parallel by our collaborators, providing the unique opportunity for direct comparisons.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.