A comprehensive research platform for measuring combustion generated soot nanoparticle morphology and pressure sensitivity at elevated pressures

为了实现更高的热效率和更小的发动机体积，内燃机被设计成在比大气高得多的压力下工作。燃气轮机和柴油机排放的主要污染物之一是煤烟，煤烟是在燃烧过程中，当运行方式为非预混或部分预混时形成的，通过增加燃烧压力，其形成速率显著提高。烟灰气溶胶通过改变大气的辐射特性，在区域和全球范围内影响地球的温度和气候。对全球变暖的贡献可能是巨大的，也许仅次于二氧化碳。此外，烟尘在冰雪上的沉积降低了地表反射率，从而捕获了辐射；这可能是全球变暖的四分之一的原因。因此，政府间气候变化专门委员会指出，烟尘气溶胶是导致气候变化的正辐射强迫的第三大贡献者。此外，接触烟尘气溶胶每年造成全球数十万人死亡。很大一部分煤烟是由陆运、空运和海运中使用的发动机排放的。控制烟尘气溶胶可以迅速产生区域和全球气候效益，并减少对人类健康的不良影响。控制方法之一是防止或减少燃烧时产生的烟尘。对燃烧中烟灰形成过程的基本理解是这种控制方法的一个组成部分。然而，由于碳氢化合物火焰的高度复杂性，燃烧过程中烟灰形成过程的化学和物理机制的细节仍然不确定，只有少数原理被牢固地建立起来，主要是在大气条件下。尽管大多数用于运输的燃烧装置都在非常高的压力下运行，但我们对高压下烟灰形成的理解还没有达到理想的水平，而且从根本上缺乏实验数据和互补的预测模型。液体生物燃料的烟尘特性尚不清楚，特别是在大多数发动机运行的高压下，这种缺乏了解的情况影响了在燃气轮机和其他陆地运输发动机中采用生物燃料和混合物。目前的要求是一个综合实验平台，包括(a)逆流扩散燃烧器系统，包括其平移台和流量计，以及(b)多角度激光散射系统，包括激光器、光电探测器和相关光学元件。所要求的平台将有助于促进对烟灰形成及其在发动机相关压力下的特征的了解，并有助于烟灰排放控制工作。这将通过使用所要求的实验平台进行仔细计划的实验来完成。

To achieve higher thermal efficiencies and smaller engine volumes, combustion engines are designed to operate at pressures much higher than the atmospheric. One of the major pollutants emitted from the gas turbines and diesel engines is soot, which forms during the combustion process when the mode of operation is non-premixed or partially premixed, and its formation rate is significantly increased by increasing the combustion pressure. Soot aerosols affect the Earth's temperature and climate, both regionally and globally by altering the radiative properties of the atmosphere. The contribution to global warming may be substantial, perhaps second only to that of CO2. In addition, the deposition of soot on snow and ice reduces the surface reflectivity thus trapping the radiation; this could be responsible for a quarter of the global warming. As a result, the Intergovernmental Panel on Climate Change states that the soot aerosol is the third largest contributor to the positive radiative forcing that causes climate change. Furthermore, exposure to soot aerosol is responsible for hundreds of thousands of global deaths each year. A significant portion of soot is emitted from engines used in land, air and sea transportation. Controls on soot aerosol can produce rapid regional and global climate benefits as well as reductions of ill effects on human health. One of the approaches in control is prevention or reduction of soot generation in combustion. A fundamental understanding of the soot formation processes in combustion is an integral part of this control approach. However, the details of the chemical and physical mechanisms of the soot formation process in combustion remain uncertain due to the highly complex nature of hydrocarbon flames, and only a few principles are firmly established mostly for atmospheric conditions. In spite of the fact that most combustion devices used for transportation operate at very high pressures, our understanding of soot formation at high pressures is not at a desirable level, and there is a fundamental lack of experimental data and complementary predictive models. Sooting characteristics of liquid bio-fuels are not known well, especially at high pressures where most engines operate, and this lack of understanding has implications in adopting bio-fuels and blends in gas turbines and other land transportation engines. The current request is for a comprehensive experimental platform consisting of (a) a counter-flow diffusion burner system including its translation stage and flow meters, and (b) a multi-angle laser scattering system comprised of a laser, photodetectors, and related optical components. The requested platform will help to contribute to the advancement of knowledge in soot formation and its characteristics at engine-relevant pressures and helping with the soot emissions control efforts. This will be accomplished by carefully planned experiments using the requested experimental platform.