Temporal and Spatiotemporal Dynamics of Chemical Reactors

化学反应器的时空动力学

• 批准号: 9416938
• 负责人: John Hudson
• 金额: $ 29.72万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-11-01 至 1998-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9416938&HistoricalAwards=false
• 关键词: Temporal; Spatiotemporal; Dynamics; Chemical; Reactors

Abstract - Hudson - 9416938 Oscillations have been known in chemical systems for some time, phenomena such as bifurcations among states, chaos, and complex spatial patterns can arise in such systems. In well-mixed open reacting systems (for example a continuous stirred tank reactor) the concentrations of reacting species can undergo periodic and chaotic oscillations. Catalytic surface reactions such as the oxidation of carbon monoxide (one of the reactions taking place in the catalytic muffler of an automobile), can also oscillate and produce spatial patterns on the catalytic surface. Electrochemical reactions, such as electrodissolution of metals, or corrosion, can exhibit temporal as well as spatial variations in reaction rate. The PI's work is focused on quantifying the above experimentally observed behavior and on developing quantitative phenomenological models. The reactions that will be studied are of both industrial and economic importance and should lead to an improved fundamental understanding of such reaction processes. Electrochemical reactions have several features which make them ideal for fundamental studies of reaction dynamics. They are relatively stationary, i.e., have less drift over the time scale of the dynamics and they exhibit many types of interesting dynamic behavior such as complex periodic oscillations, low order chaos, spatiotemporal patterns, etc. Also, there are easily controlled parameters (the potential or current as well as the mass transfer coefficient near a rotating disk) so that transitions among states can be investigated. The PI will study the temporal and spatiotemporal dynamics of chemically reacting systems. In the temporal studies, time series emanating from the electrochemical dissolution of metals will be investigated. The studies are to be both deterministic and stochastic. In the former, chaotic behavior and transitions, or bifurcations, between states will be emphasized, applying methods from nonlinear dynamics to the experimental data in order to identify and characterize the underlying dynamics of the system and to develop phenomenological mathematical models. A new research program in electrochemical noise associated with localized corrosion will be initiated, consisting of both experimental and modeling studies. Spatiotemporal dynamics will be studied by using a video camera to record spatial nonuniformities. The work is aimed at developing models which should help answer questions such as how do films grow and recede on dissolving metals, how much interaction is there among pits on the surface of corroding metals, and under what conditions is synchronization among reacting sites local or global in nature. ***

摘要-哈德逊- 9416938 化学系统中的振荡现象已经存在了一段时间，在这样的系统中会出现状态间的分叉、混沌和复杂的空间模式等现象。 在充分混合的开放反应系统（例如连续搅拌釜反应器）中，反应物质的浓度可以经历周期性和混沌振荡。 催化表面反应，如一氧化碳的氧化（在汽车的催化消声器中发生的反应之一），也可以振荡并在催化表面上产生空间图案。 电化学反应，例如金属的电溶解或腐蚀，可以表现出反应速率的时间和空间变化。 PI的工作重点是量化上述实验观察到的行为和发展定量的现象学模型。 将要研究的反应具有工业和经济重要性，并且应该能够提高对此类反应过程的基本理解。 电化学反应有几个特点，使它们成为反应动力学基础研究的理想选择。 它们是相对静止的，即，具有较小的漂移的动态的时间尺度上，他们表现出许多类型的有趣的动态行为，如复杂的周期振荡，低阶混沌，时空模式等，也有很容易控制的参数（潜在的或电流以及附近的旋转盘的传质系数），使国家之间的过渡可以进行调查。 PI将研究化学反应系统的时间和时空动力学。 在时间研究中，将研究金属电化学溶解产生的时间序列。 这些研究既有确定性，也有随机性。 在前者，混沌行为和过渡，或分叉，状态之间的将被强调，应用方法从非线性动力学的实验数据，以确定和表征系统的基本动力学和发展唯象数学模型。 一个新的研究计划，电化学噪声与局部腐蚀将启动，包括实验和建模研究。 时空动力学将通过使用摄像机记录空间不均匀性来研究。 这项工作的目的是开发模型，这应该有助于回答的问题，如如何膜生长和消退溶解金属，有多少相互作用之间的腐蚀金属表面上的坑，并在什么条件下是同步的反应站点之间的本地或全球的性质。 ***