Mixed Convection Gas Transfer across Surfactant-Contaminated Air/Water Interfaces

跨表面活性剂污染的空气/水界面的混合对流气体传输

• 批准号: 0500155
• 负责人: John Saylor
• 金额: --
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0500155&HistoricalAwards=false
• 关键词: Mixed; Convection; Gas; Transfer; across

National Science FoundationABSTRACTProposal Number: CTS-0500155Principal Investigator: John SaylorAffiliation: Clemson University Proposal Title: Mixed Convection Gas Transfer Across Surfactant-Contaminated Air/Water InterfacesThis proposal was received as an unsolicited submission to the Chemical and Transport Systems Division and was funded by the Thermal Transport and Thermal Processing Program. The transfer of dissolved gases across the air/water interface of freshwater lakes is critical to numerous ecosystems. Protection of these ecosystems requires an understanding of this interfacial gas exchange problem. While there is a large body of research on gas exchange across air/water interfaces at the high wind speed conditions typical of oceans, little has been done to study the low wind speed conditions that are common on lakes. The proposed research seeks to address this critical need, focusing on the transport of dissolved gases such as oxygen and carbon dioxide, under low wind speed conditions where both forced convection and natural convection play a role; a transport regime referred to as mixed convection. This research will also focus on how gas transfer is affected by the single molecule thick organic films called 'surfactant monolayers', which are ubiquitous on lakes. The research will consist of a set of laboratory experiments utilizing a wind/water tunnel where the transfer of dissolved gases such as oxygen and carbon dioxide will be measured as a function of wind speed and air-water temperature difference. The effect of surfactant contamination on transport will be quantified by introducing these surfactants on the water surface in a controlled fashion. The fluid flow structures responsible for the observed gas exchange phenomena will be investigated using flow visualization techniques, including infrared imaging of the water surface and laser induced fluorescence imaging of the subsurface flow. The proposed research will result in improved models of the effect of human activity on lakes, more accurate global climate change models, and improvements in the efficiencies of numerous industrial processes.

国家科学基金会摘要提案编号：CTS-0500155主要研究者： 约翰·赛罗所属单位： 克莱姆森大学提案标题：通过表面活性剂污染的空气/水界面的混合对流气体传输本提案是作为主动提交给化学和运输系统部的，并由热运输和热处理计划资助。溶解气体通过淡水湖的空气/水界面的转移对许多生态系统至关重要。 保护这些生态系统需要了解这种界面气体交换问题。 虽然有大量的研究在高风速条件下的典型海洋的空气/水界面的气体交换，很少有人做研究低风速条件下，是常见的湖泊。 拟议的研究旨在解决这一关键需求，重点是在低风速条件下，强制对流和自然对流都发挥作用的溶解气体（如氧气和二氧化碳）的运输;运输制度被称为混合对流。 这项研究还将集中在如何气体传输是由单分子厚的有机膜称为“表面活性剂单分子层”，这是无处不在的湖泊影响。 该研究将包括一套利用风洞/水洞的实验室实验，其中将测量溶解气体（如氧气和二氧化碳）的转移，作为风速和空气-水温差的函数。 表面活性剂污染对运输的影响将通过以受控方式在水面上引入这些表面活性剂来量化。 负责所观察到的气体交换现象的流体流动结构将使用流动可视化技术，包括红外成像的水面和激光诱导荧光成像的地下流进行调查。 拟议的研究将改进人类活动对湖泊影响的模型，更准确的全球气候变化模型，并提高许多工业流程的效率。