U.S.-Hungary Joint Fund Research: Convection Induced by Chemical Waves

美国-匈牙利联合基金研究：化学波引起的对流

• 批准号: 9220788
• 负责人: George Bazsa
• 金额: --
• 依托单位: Kossuth Lajos Science University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-15 至 1996-01-15
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9220788&HistoricalAwards=false
• 关键词: U.S.; Hungary; Joint; Fund; Research

This US-Hungary Joint Fund research on "Convection Induced by Chemical Waves" will be conducted by Dr. George Bazsa of Kossuth Science University in cooperation with Dr. John A. Pojman of the University of Southern Mississippi. Autocatalytic reactions (in which the products increase the rate of their own production) can propagate in unstirred solutions. The reactions can alter the density of the solution by releasing heat (decrease the density) and by changing the composition of the solution (either increase or decrease the density). Under the influence of gravity the resulting density gradients can result in fluid motion, or natural convection. The effect of convection on the rate of front propagation in the iron-nitric acid system has been shown to exhibit puzzling dependence on the orientation of the tube and the initial concentrations. The mechanism of the convection is still not clear. Besides raising basic questions about the interactions of chemistry and hydrodynamics, this work may aid in understanding chemically induced convection in other areas such as directional solidification and wet chemical etching. This study will measure the concentration gradients and thermal gradients in traveling fronts using video imaging technology in order to test mechanisms proposed for the convection which has been observed, and often, only inferred from measurements of propagation. Chemically induced convection systems offer insight into natural convection in small containers. The orientation dependence of fluid flow with respect to the gravitational vector is especially relevant to materials processing in space, where there is reduced gravity but greater difficulty in controlling the orientation of the container with respect to the gravitational vector. This research in chemistry fulfills the program objective of advancing science by enabling leading experts in the United States and Hungary to combine complementary talents and pool research resources in areas of strong mutual interest and competence.

这项关于“化学波引起的对流”的美匈联合基金研究将由科苏斯科学大学的 George Bazsa 博士与南密西西比大学的 John A. Pojman 博士合作进行。 自催化反应（其中产物提高其自身生产速率）可以在未搅拌的溶液中传播。 反应可以通过释放热量（降低密度）和改变溶液的成分（增加或减少密度）来改变溶液的密度。 在重力的影响下，产生的密度梯度会导致流体运动或自然对流。 铁-硝酸系统中对流对前沿传播速率的影响已被证明对管的方向和初始浓度表现出令人费解的依赖性。 对流的机制仍不清楚。 除了提出有关化学和流体动力学相互作用的基本问题外，这项工作可能有助于理解其他领域的化学诱导对流，例如定向凝固和湿法化学蚀刻。 这项研究将使用视频成像技术测量行进锋面的浓度梯度和热梯度，以便测试为已观察到的对流提出的机制，并且通常仅从传播测量中推断出对流。 化学诱导对流系统可以深入了解小容器中的自然对流。 流体流相对于重力矢量的方向依赖性与空间中的材料加工尤其相关，其中重力减小，但控制容器相对于重力矢量的方向更加困难。 这项化学研究通过使美国和匈牙利的领先专家能够在共同感兴趣和能力强的领域结合互补人才并汇集研究资源，实现了推进科学发展的计划目标。