Fundamental and Applied Studies in Chemical Reacting Flows

为了与探索基金的目标保持一致，拟议的工作是以计划为基础的。它包含基础和应用研究，以及广泛地解决研究化学反应流动的两个核心动机。这项研究的目的是增进对控制和管理以下方面所需的认识：(A)碳氢资源燃烧对环境的影响；(B)与燃烧过程有关的化学能到热能的转化率。*供暖用天然气脱碳项目：世界正在从主要以碳(例如，煤和石油，以及程度较低的天然气)的形式储存能量的化石燃料过渡到净零碳循环的系统。正在探索一种专门用于加热应用的工艺，看看天然气中烷烃中的元素是否可以在零氧环境下通过热分解经济地分解为黑碳和氢。然后，这些组分可以根据它们的密度很容易地分离出来，将碳作为固体捕获，同时将热氢送出去燃烧，在典型温度下需要它的产物。最终的结果是，处理的天然气是最初用于供暖的天然气的两倍，但没有二氧化碳排放。这个项目还包括对捕获的黑碳进行表征，以确定它是否对轮胎、橡胶、油漆、油墨或电极有价值。*项目B-不稳定在模拟高达科勒数预混湍流火焰中的作用：我们对非稳定流动和燃速之间相互作用的现象学理解不如对稳定火焰的理解。大多数实际的火焰都是动荡的，所以它们充满了不稳定。这项研究的目的是确保在模拟预混火焰的燃烧速度时适当地考虑这些非定常影响。特别令人感兴趣的是火焰对流动特征的响应方式，这些流动特征具有与火焰化学相同的时间尺度。当这些时间尺度相互接近时，火焰热释放的响应在相位滞后和幅度方面受到深刻的影响。根据反应物的当量比，这可能发生在低至100赫兹的频率上。因此，非直接数值模拟(即大涡模拟和G方程模型)忽略了热释放的时间(因此位置)和幅度。我们正在采取的方法是基于简单的直接数值模拟来开发火焰传递函数，并向研究复杂湍流的人提供模型。*综合而言，这项研究将有助于更负责任和环境可持续地使用碳氢燃料。

In keeping with the objectives of a Discovery Grant, the proposed work is program-based. It contains fundamental and applied research, as well as broadly addressing two core motivations for studying chemical reacting flows. This research is aimed at advancing the understandings needed to control and manage: (A) the environmental impacts of the combustion of hydrocarbon resources; and, (B) the rates of conversion of chemical energy to thermal energy associated with combustion processes. ******Project A Decarbonization of Natural Gas for Heating Applications: The world is transitioning away from fossilize fuels that primarily store their energy in the form of carbon (e.g., coal and oil, and to a lesser degree natural gas), which introduces “new” carbon dioxide into the atmospheric when it is burned, to a system with net-zero carbon cycle. A process is being explored, specifically for heating applications, to see if the elements in the alkanes in natural gas can be economically partitioned through thermal decomposition in a zero-oxygen environment into black carbon and hydrogen. These components can then be easily separated based on their density, capturing the carbon as a solid while sending the hot hydrogen off for combustion where its products are needed at their typical temperatures. The net result is that twice as much natural gas is processed as originally burned for the heating application, but there are no carbon dioxide emissions. This project also involves the characterization of the captured black carbon to see if it has value for tires, rubber, paint, inks, or electrodes.******Project B - Role of Unsteadiness in Modelling Premixed Turbulent Flames at High Damkohler Numbers: Our phenomenological understanding the interactions between unsteady flows and burning rates is not as well developed as for steady flames. Most practical flames are turbulent, so they are rife with unsteadiness. The objective of this study is to ensure that these unsteady effects are properly accounted for in modelling the burning rate of premixed flames. Of particular interest is the way that flames respond to flow features that have time scales of the same order as the flame chemistry. As those time scales approach each other the response of the flame's heat release are profoundly affected in terms of phase lag and amplitude. Depending on the equivalence ratio of the reactants this may occur at frequencies as low as 100 Hz. Consequently, non-direct numeric simulations (i.e., large eddy simulations and G-equation models) miss the time (and hence location) and amplitude of heat release. The approach we are taking is to develop flame transfer functions based on simple direct numeric simulations and make models available to those studying complex turbulent flows.******Taken collectively, this research will contribute to more a responsible and environmentally sustainable use of hydrocarbon fuels.**