标题： 不同氧化环境中的单个硅颗粒燃烧行为 显示英文标题

标题： Combustion Behaviour of Single Silicon Particles in Different Oxidizing Environments

摘要： 尽管硅的丰富性和高能量密度，它作为无碳燃料仍研究不足，关于其燃烧特性的数据有限。在本工作中，使用静电悬浮器和激光点火研究了硅颗粒的燃烧行为。在常压下研究了五种氧化环境：空气、纯氧以及含有40%氧气（摩尔分数）并用氮气、氦气或氩气稀释的混合气体。通过三色测温法测量的燃烧液滴峰值温度，从空气到纯氧增加了337 K。在40%O2-60%He混合气体中的硅液滴峰值温度低于在40%O2-60%Ar混合气体中的峰值温度，这与热力学预测相矛盾，这是由于氦气稀释混合物的Lewis数较高。尽管氦气稀释混合物中的氧气扩散率更高，但观察到的燃烧速率较低，这归因于较低的燃烧温度。高速彩色摄像机观测显示，在每次燃烧过程中，颗粒直径的平方随时间减少，并且在所有氧化环境中都遵循强线性关系（R2 > 0.99）。然而，燃烧寿命与初始颗粒直径的n次方成正比，n的范围从1.69到1.82。这种与预期n = 2的偏差似乎是由于不可避免的测量不确定性以及颗粒尺寸范围有限，而不是燃烧物理差异所致。燃烧过程中硅液滴尺寸的减少归因于气态SiO作为中间燃烧产物的形成。使用紫外相机观察到了SiO物种，显示出从颗粒表面的紫外强度衰减。高速成像和LED吸收信号表明，最终的凝聚产物SiO2纳米颗粒不可见，表明它们具有非常低的发射率。 显示英文摘要

摘要： Silicon, despite its abundance and high energy density, remains underexplored as a carbon-free fuel, with limited data available on its combustion characteristics. In this work, the combustion behaviour of silicon particles is examined using an electrostatic levitator with laser ignition. Five oxidizing environments at atmospheric pressure are investigated: air, pure oxygen, and mixtures containing 40% oxygen (by mole) diluted with nitrogen, helium, or argon. The burning droplet peak temperature, measured by three-colour pyrometry, increases by 337 K from air to pure oxygen. The peak temperature of the silicon droplet in the 40%O2-60%He mixture is lower than that in the 40%O2-60%Ar mixture, in contradiction with thermodynamic predictions, due to a higher Lewis number of the helium-diluted mixture. Although oxygen diffusivity is higher in the helium-diluted mixture, a lower burning rate is observed, attributed to the lower combustion temperature. High-speed colour camera observations reveal that the square of the particle diameter decreases with time in each combustion run, following a strong linear relationship (R2 > 0.99) across all oxidizing environments. However, the combustion lifetime is proportional to the initial particle diameter to the power of n, with n ranging from 1.69 to 1.82. This deviation from the expected n = 2 appears to result from unavoidable measurement uncertainties and the limited particle size range, rather than differences in combustion physics. The decrease in silicon droplet size during combustion is attributed to the formation of gaseous SiO as an intermediate combustion product. The SiO species is observed using a UV camera, showing a UV intensity decay from the particle surface. High-speed imaging and LED absorption signals indicate that the final condensed product, SiO2 nanoparticles, are not optically visible, suggesting they possess very low emissivity.