Enhancing the Scientific Understanding of Nanoparticle Formation in Flames

点击翻译按钮获取中文摘要

Combustion-derived nanoparticles, such as soot, are known to have adverse effects on human health and the environment. In terms of health effects, soot particles have been linked to heart and lung disease, along with various other health complications. In terms of environmental effects, soot is considered to be one of the most significant contributors to global warming, behind CO2, due to its strong radiative properties. For these reasons, stricter regulations are now targeting particulate emissions in both automotive and aviation engines. A fundamental understanding of soot formation is needed in order to develop predictive models and better combustor designs. With stricter regulations come into place, industry has a strong desire for accurate predictive soot models to aid the design process. However there is an urgent need for a more fundamental understanding as many soot formation and oxidation processes are poorly understood. These processes include polycyclic aromatic hydrocarbon (PAH) formation, soot inception, soot nucleation, soot growth by the addition of small hydrocarbon species, and soot growth by PAH adsorption on the surface. The long term vision of my research is to develop a robust model of soot formation that can predict the mass, size distribution and aggregate structure of soot in flames. The model would need to predict how the soot formation changes as we change the flame’s temperature, pressure, fuel structure, mixing and residence time. In order to achieve this, the model would need to be based on fundamental processes and avoid fitted parameters (as is the case today). Detailed experimental measurements are needed in a variety of flame conditions to investigate these processes and rigorously validate the model. Short term objectives include (1) addressing each soot formation process that is currently not well understood, (2) developing a comprehensive dataset of soot formation for a relevant set of fuel molecules and (3) developing an experimental setup for premixed stagnation flames. Thus a model of soot formation will be developed that (1) captures the fundamental physics that is occurring and reduces the number of adjusted parameters that are currently fitted to experiments, (2) focuses on fuel molecules relevant to practical fuels and (3) is validated on a wide range of non-premixed and premixed flame experiments. The multidisciplinary nature of soot formation makes it an excellent training area for students in the thermo-sciences research area. It provides a comprehensive background in the thermo-sciences as understanding sooting flames requires knowledge of processes such as fluid dynamics, mass and heat transfer, thermodynamics, aerosol dynamics, chemical reactions, phase change and radiation heat transfer. This opens opportunities for students in a wide range of thermo-science fields.