CAREER:Understanding Sponteneous Combustion of Hydrogen and Oxygen in Nanobubbles

【摘要】本文主要研究电解生成的水纳米气泡形成的纳米密闭环境中氢、氧的点火与燃烧。据推测，点火和燃烧的原因是：(1)限制缩短了有效平均自由程，从而提高了分子碰撞、反应和热释放的速率，从而克服了小型燃烧装置中常见的重大热损失，或者(2)在气泡崩溃期间压力增加，类似于快速压缩机，导致反应物混合物的点火和燃烧。实验工作集中在气泡大小、生长动力学和气泡内温度的测量上。扫描激光多普勒振动法用于测量气泡的大小和演变，而微加工技术则用于生产适用于相关小时间和空间长度尺度的纳米尺度温度计。这项研究旨在弥合纳米科学和传统燃烧科学之间的差距，传统燃烧科学通常与更大规模的系统（如发动机）有关。潜在的好处包括在真正的纳米尺度上理解点火和燃烧，应用于小型能源系统、机械和消防安全。采用分子动力学方法来确定纳米气泡内H2/O2混合物的压力和化学反应，以帮助减轻所提出的小规模实验的困难。该教育项目要求对公众进行教育，通过一个受欢迎的纳米科学网站传播研究成果，为本科生提供研究机会，并招募和指导女性工程研究生。

Abstract1254648Qiao, LiThe proposed study is focused on ignition and combustion of hydrogen and oxygen in nano-sized confinements formed by water nano-bubbles, which are generated by electrolysis. It is hypothesized that ignition and combustion results from either (1) the confinement shortening the effective mean free path resulting in higher rates of molecular collision, reaction, and heat release to overcome the significant heat loss commonly encountered in small combustion devices, or (2) the pressure increase during the collapse of the water bubble resembling that in a rapid compression machine that leads to ignition and combustion of the reactant mixture. Experimental efforts concentrate on measurements of bubble size, growth dynamics, and temperature within the bubble. Scanning laser-Doppler vibrometry is used for determining bubble size and evolution, while micro fabrication techniques are used to produce nano-scale thermometer suitable for the associated small time and spatial length scales. The study is aimed at bridging the gap between nano-science and traditional combustion science that are usually associated with systems of much larger scales such as engines. Potential benefits include understanding ignition and combustion at truly nano-scales, with applications in small energy systems and machinery and fire safety. A Molecular Dynamics approach is adopted for determining the pressure and chemical reactions of the H2/O2 mixture within the nano-bubble To help alleviate the difficulties in the proposed small-scale experiments. The educational program calls for education of the public, dissemination of research through a popular nano-science website, research opportunities for undergraduate students, and recruitment and mentoring of woman engineering graduate students.