Infrared Evaporative Absorption and Condensative Emission in Water

水中红外蒸发吸收和冷凝发射

• 批准号: 1062361
• 负责人: M Q Brewster
• 金额: $ 33.34万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2016-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1062361&HistoricalAwards=false
• 关键词: Infrared; Evaporative; Absorption; Condensative; Emission

1062361BrewsterAbstract The objective of this project is to investigate infrared radiation emission and absorption associated with first-order, vapor-liquid and vapor-solid phase transitions in water. Water undergoing condensation and evaporation plays a vital role in many engineering systems as well as in the environment. Heat exchangers are pervasive in society and water condensation, vaporization, sublimation and deposition are critically important in the performance of these devices. Drying is another important industrial process involving water vaporization that is very energy intensive. In the environment water plays a crucial thermal regulation role and its phase changes have a significant effect on Earth's energy balance through latent heat effects. It is also well known that water, in all three phases, plays an important role in atmospheric and surface radiative transfer via volumetric (single-phase) emission, absorption, and scattering. What is not well recognized is that vapor-liquid and vapor-solid water phase-transitions also may play a potentially critical role in surface and atmospheric radiative transfer. In spite of extensive knowledge of water's bulk, volumetric infrared properties, surface radiative properties associated with first-order phase transitions are almost unrecognized. In this study both measurements and modeling of phase-change radiation involving vapor and condensed-state transitions will be conducted. A laboratory-scale test chamber will be constructed and used to measure infrared emission and absorption by water droplets tens of microns and smaller in size undergoing vapor-liquid phase transition. The closed chamber will operate isobarically under steady-state and transient heating/cooling conditions. Surface (phase-change) emission/absorption will be delineated from volumetric emission/absorption by analytic data reduction techniques including Monte Carlo methods. A unified molecular model will be developed covering solid-, liquid-, and vapor-states that describes both new surface radiative phase-change properties and volumetric (single-phase) radiative properties. This study has intellectual merits at levels ranging from fundamental, scientifically oriented to engineering oriented. New knowledge will be generated about radiative phase- transitions for one of the most important substances on the planet. The infrared emission measurements will generate new knowledge about liquid-vapor radiative phase transitions of water for both condensation and vaporization. These measurements will be used to develop a model for liquid-water structure. At the engineering level, new data and a mathematical model for infrared emission and absorption by water will be developed. This study will also have broader impacts, ranging from individuals to society at-large. At the individual level this study will most immediately affect the education and career of graduate and undergraduate students. Locally, workshops will be conducted for K-12 students on water properties, phase-change heat transfer, and global climate change. At the engineering level the radiative phase-transition findings obtained herein will allow a better fundamental understanding of energy transfer in heat exchanger and drying equipment. At a larger, societal level, these findings may open a door to improved microphysical modeling of atmospheric energy transfer processes. The ultimate broad impact of this project will be better understanding of the fundamental thermophysical properties of our industrial society's primary thermal regulating fluid and Earth's principal greenhouse gas: water.

1062361brewstertractrats该项目的目的是研究水中与一阶，蒸气和蒸气 - 固相变相关的红外辐射发射和吸收。 经历冷凝和蒸发的水在许多工程系统和环境中都起着至关重要的作用。 热交换器在社会和水冷凝，蒸发，升华和沉积中具有广泛性，这对于这些设备的性能至关重要。 干燥是另一个重要的工业过程，涉及水蒸气，这是非常强大的。 在环境中，水具有至关重要的热调节作用，其相变的变化通过潜在的热效应对地球能量平衡产生了重大影响。 众所周知，在这三个阶段中，水在大气和表面辐射转移中都起着重要作用，这是通过体积（单相）发射，吸收和散射的。尚未得到充分认识的是，蒸气 - 液体和蒸气固定水相过渡也可能在表面和大气辐射转移中起潜在的关键作用。 尽管对水的大量知识，体积红外特性，但与一阶相变相关的表面辐射特性几乎没有识别。 在这项研究中，将进行涉及蒸气和冷凝状态转变的相变辐射的测量和建模。 将建造一个实验室规模的测试室，并用于测量数十微米的水滴和较小的水滴的红外发射和吸收，并且经历了蒸汽液相变的尺寸。 封闭的腔室将在稳态和瞬态加热/冷却条件下进行等同的操作。 通过包括蒙特卡洛方法在内的分析数据还原技术，将从体积发射/吸收中描绘出表面（相变）的发射/吸收。将开发一个统一的分子模型，涵盖固体，液体和蒸气状态，这些固体，液体和蒸气园描述了新的表面辐射相变特性和体积（单相）辐射特性。这项研究具有智力优点，范围从基本，以科学为导向到以工程为导向。关于地球上最重要的物质之一的辐射相转变，将产生新的知识。红外排放测量将产生有关水的液体蒸气辐射相变的新知识，以进行凝结和汽化。这些测量将用于开发用于液体水结构的模型。在工程水平上，将开发新的数据和用于红外发射和吸收水的数学模型。 这项研究还将产生更广泛的影响，从个人到社会一般。在个人层面上，这项研究将最立即影响研究生和本科生的教育和职业。在当地，将为K-12学生开设有关水性能，相变传热和全球气候变化的研讨会。在工程水平上，此处获得的辐射相转换结果将使人们对热交换器和干燥设备中的能量转移有更好的基本了解。在更大的社会层面上，这些发现可能打开了改善大气能量转移过程的微物理建模的门。该项目的最终广泛影响将更好地理解我们工业学会主要调节流体和地球主要温室气体的基本热物理特性：水。