Development of an additively manufactured research burner for increased energy efficiency

鉴于全球变暖，无碳能源对于减少向大气中的CO2排放至关重要。含碳燃料（例如醇）的替代物是氨（NH3）和/或氢（H2），两者都是无碳的。因此，这些气体燃料的组合，或将它们添加到常规或合成雾化液体燃料中，可导致碳减少或甚至无碳能源的极大改进。这些燃料系统的非常复杂的组合燃烧是本研究的背景。在这种情况下，开发了一种耐高温、耐腐蚀、增材制造的智能燃烧器，以提高能源效率并减少污染物的形成。增材制造（AM）能够生成具有高度设计自由度的独特组件，并有可能实现复杂的（内部）几何形状。在这里，AM的优势通过集成功能设计得到了理想的利用，例如弯曲的介质进料通道，开放的多孔结构，以及带有集成传感器的组件组的直接制造。选择的材料是镍基合金（MAR-M247），这是一种经过验证的高温相关应用材料。从燃烧的角度来看，本项目的重点是添加氨和/或氢的液体生物醇，如甲醇，乙醇，或正丁醇，以减少二氧化碳的排放量。无碳燃料可以作为气体或液体（在降低的温度下）注入，或者溶解在增材制造的燃烧器中的液体燃料中。后一种方法需要对氢和氨在生物燃料中的溶解度以及液体的雾化和蒸发特性有深刻的了解。所设计的燃烧器是非常灵活的，并且允许预混合的气态燃料或氨与氧化剂的喷射，使得包括预混合、部分预混合和非预混合燃烧的不同燃烧状态共存。这些选项确保了燃料及其喷射的极高灵活性。用于将氨直接喷射到热火焰区中的可变环能够改善氨在点火和火焰速度方面的不良燃烧特性。对喷射器附近的过程进行建模、模拟和实验的结合，沿着增材制造燃烧器技术的贡献，为理想的无碳能源运输部门减少全球变暖提供了极好的知识增益。

In view of global warming, carbon-free energy sources are of utmost importance for the reduction of CO2 emissions into the atmosphere. Alternatives to carbon-containing fuels, such as alcohols, are ammonia (NH3) and/or hydrogen (H2), both of which are carbon free. Thus, a combination of these gaseous fuels, or their addition to either conventional or synthetic atomized liquid fuels, may lead to a great improvement of carbon-reduced or even carbon-free energy sources. The very complex combined combustion of these fuel systems is the background for this investigation. In this context, a high-temperature and corrosion resistant, additively manufactured and smart burner is developed to increase energy efficiency and to reduce pollutant formation. Additive Manufacturing (AM) enables the generation of unique components with a high degree of design freedom and the possibility to realize complex (internal) geometries. Here, the advantages of AM are ideally exploited by integrated functional designs, such as curved media feeding channels, open porous structures, and the direct manufacturing of assembly groups with integrated sensors. The material of choice is a Nickel base alloy (MAR-M247), which is a proven material for high temperature relevant applications. From a combustion perspective, the present project focuses on the addition of ammonia and/or hydrogen to liquid bio-alcohols, such as methanol, ethanol, or n-butanol, in order to reduce the CO2 emissions. The carbon-free fuels may be injected as gases or liquids (at reduced temperatures) or be dissolved in the liquid fuel in the additively manufactured burner. The latter method requires profound knowledge of the solubility of hydrogen and ammonia in biofuels, as well as the atomization and evaporation characteristics of the liquid. The projected burner is extremely flexible and allows for the injection of the premixed gaseous fuels or of the ammonia with the oxidizer so that different combustion regimes including premixed, partially premixed, and non-premixed combustion coexist. These options ensure an extremely high flexibility of the fuels as well as their injection. A variable ring to inject the ammonia directly into the hot flame zone enables the improvement of the poor combustion properties of the ammonia with respect to the ignition and the flame speed. The combination of modeling, simulations, and experiments of the processes near the injector, along with contributions from additively manufactured burner technology, provide excellent knowledge gains in reducing global warming in an ideally carbon-free energy transportation sector.