Chemical-to-mechanical energy conversion at fluid interfaces: study of the fundamental properties and applications

流体界面处的化学能到机械能的转换：基本性质和应用的研究

• 批准号: RGPIN-2014-06186
• 负责人: Krechetnikov, Rouslan
• 金额: $ 1.97万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=588859
• 关键词: Chemical; mechanical; energy; conversion; fluid

The second law of thermodynamics puts a fundamental limit on the efficiency of all heat engines: the Carnot theorem tells us that the efficiency coefficient should be less than the difference between the absolute temperatures of the hot and cold heat reservoirs normalized by that of the hot reservoir. On the other hand, all motor organs in living organisms, known for their efficiency, operate through the conversion of chemical energy directly into mechanical motion under almost isothermal conditions, i.e. through mechanisms other than the Carnot cycle. The proposed research is motivated by the fundamental and practical importance of the direct conversion of chemical energy into mechanical motion and will be performed in the context of complex fluid interfaces. The goals are to elucidate the physical origin and quantify the dynamics of self-sustained motions and topological changes of such interfaces. Since the motions arise due to interfacial (Marangoni) instabilities, driven by surface-active substances (surfactants) produced by chemical reactions, we will achieve these goals by (1) identifying the conditions when such instabilities occur, and (2) uncovering the role of interfacial singularities in sustaining such motions. Among the practical questions to be addressed are: what are the feasible system geometries and physical conditions for the most efficient operation of various devices based on self-sustained motions? This research effort will require novel theoretical tools and experimental capabilities. On the experimental side, in the laboratory we will study self-sustained motions as well as design and test isothermal motors based on them. While a limited number of such chemical reactions leading to interfacial motions have been identified in the literature, whether or not these are the most energy-efficient choices has yet to be determined. On the theoretical side, as a part of the longer-term objective, this work will lead to elaboration of new geometrically inspired (coordinate-free) theoretical methods based on the synergy of dynamical systems, differential geometry, singularity theories, and nonequilibrium thermodynamics. Such a theoretical framework for studying self-induced interfacial motion phenomena is a necessary step towards developing reliable computational methods for these multiscale systems, and designing real applications with desired functions. The proposed program will also help us to understand the interplay between singularity and instability phenomena and thus to make progress on Arnold's problem of unifying Cartan's and singularity theories. This work draws on the PI's unique combined expertise in both theoretical and experimental interfacial fluid dynamics as well as geometric methods of analysis. The experiments will be performed in the PI’s laboratory, the infrastructure for which is provided by both the Mechanical Engineering and Physics Departments.

热力学第二定律对所有热机的效率提出了一个基本限制：卡诺定理告诉我们，效率系数应该小于热库和冷库的绝对温度之差。另一方面，以其效率而闻名的活生物体中的所有运动器官都通过在几乎等温的条件下将化学能直接转化为机械运动来操作，即通过卡诺循环以外的机制。拟议的研究的动机是化学能直接转化为机械运动的基本和实际的重要性，并将在复杂的流体界面的背景下进行。其目标是阐明的物理起源和量化的动力学的自我维持的运动和拓扑变化的接口。由于运动是由于界面（Marangoni）不稳定性引起的，由化学反应产生的表面活性物质（表面活性剂）驱动，我们将通过以下方式实现这些目标：（1）确定这种不稳定性发生的条件，以及（2）揭示界面奇点在维持这种运动中的作用。其中要解决的实际问题是：什么是可行的系统几何形状和物理条件的最有效的操作的各种设备的基础上自我维持的运动？ 这项研究工作将需要新的理论工具和实验能力。在实验方面，我们将在实验室中研究自持运动，并设计和测试基于它们的等温电机。虽然在文献中已经确定了有限数量的导致界面运动的这种化学反应，但这些反应是否是最节能的选择还有待确定。在理论方面，作为长期目标的一部分，这项工作将导致新的几何启发（坐标自由）理论方法的基础上，动力系统，微分几何，奇点理论和非平衡态热力学的协同作用的阐述。这样一个理论框架研究自诱导界面运动现象是一个必要的步骤，发展可靠的计算方法，这些多尺度系统，并设计真实的应用所需的功能。所提出的方案也将有助于我们理解奇异性和不稳定现象之间的相互作用，从而使阿诺德的问题，统一的Cartan和奇异性理论的进展。 这项工作借鉴了PI在理论和实验界面流体动力学以及几何分析方法方面的独特综合专业知识。实验将在PI的实验室进行，基础设施由机械工程和物理系提供。