Collaborative Research: Supercritical Fluids and Heat Transfer - Delineation of Anomalous Region, Ultra-long Distance Gas Transport without Recompression, and Thermal Management

合作研究：超临界流体与传热——异常区域的描绘、无需再压缩的超长距离气体传输以及热管理

• 批准号: 2327571
• 负责人: Vishwanath Prasad
• 金额: $ 37.07万
• 依托单位: University of North Texas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2327571&HistoricalAwards=false
• 关键词: Collaborative; Research; Supercritical; Fluids; Heat

Fluids under supercritical (SC) conditions, where distinct liquid and gas phases no longer exist, are found in nature and technological systems that can take advantage of the extreme changes that take place near the critical temperature and pressure. The increases in heat transfer, reductions in fluid friction, and high solubility of SC fluids have current and potential applications in pipeline transport of natural gas, delivery of carbon dioxide as part of carbon capture and storage processes, working fluids for thermal and nuclear power plants, solar and geothermal energy conversion systems, and enhanced cooling of electronic devices and data centers. Despite the advantages offered by the unique properties of SC fluids, their wide-spread use has been curtailed because of inadequate understanding of anomalous behaviors, characterized by large-scale variations in thermophysical properties in the critical region, resulting in thermal and flow oscillations and other detrimental phenomena. Additionally, the critical temperature and pressure range, specific to each substance, may not fit a particular technological need. This research will address the anomalous behavior knowledge gaps of an important set of SC fluids, which will open the door to new technologies for high-capacity, energy-efficient, and environmentally responsible fluid flow and thermal management systems. For example, natural gas under SC conditions (SNG) can be transported via overland, underground, and undersea pipelines for distances greater than 2,000 km. SNG transport is power-efficient and can reduce the number of enroute recompression stations or eliminate them altogether, enabling new trans-oceanic routes that are currently impossible, serving the US national interest as well as providing energy security elsewhere in the world. In comparison with liquified natural gas (LNG), SNG transport can be less expensive, have reduced environmental impact, and be more secure and safe. Knowledge generated in the study of SNG transport will be useful in determining the thermodynamic states of carbon dioxide when it is transported from shorelines to the ocean floor for sequestration. Likewise, development of methods to transport SC oxygen, nitrogen, and other important industrial/medical gases will benefit from this work. The broader impacts of this research include educational opportunities in SC transport phenomena and outreach to underrepresented groups using the wide range of current and potential SC technologies to motivate interest in thermodynamics.Previous research has shown that anomalous fluid transport behavior near the critical point starts in the subcritical state above the triple point and continues deep into the SC state. In this research program, a thermodynamic model based on Gibbs free energy will be developed to delineate the temperature-pressure boundaries of the anomalous states and characterize the higher-order phase transitions. It will be applied to a set of naturally/industrially important SC fluids including water, carbon dioxide, methane, argon, and nitrogen. This analysis will lead to the identification of safe conditions at which SC fluids, including supercritical natural gas (SNG), can be transported over long distances without recompression. The full potential for SNG transport will be quantified by developing a one-dimensional computational model for SC thermal transport, accounting for transport property variations and compressibility, environmental thermal conditions, Joule-Thomson phenomena, and thermal resistance of the pipeline. A three-dimensional model will be developed to examine the flow and thermal behavior in the inlet and outlet regions as well as the impact of temperature variations in the surrounding environment. The thermodynamic models also will be employed to design customized mixtures of SC fluids for effective thermal management. The proposed research includes plans to fabricate an experimental apparatus for SC fluid flow and thermal analysis to generate data relevant to SC fluid properties, examine parametric effects for model validation, and explore methods to enhance heat transfer.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

超临界（SC）条件下的流体，即不再存在不同的液相和气相，存在于自然和技术系统中，可以利用临界温度和压力附近发生的极端变化。 SC 流体的传热增加、流体摩擦减少以及高溶解度在天然气管道运输、作为碳捕获和存储过程一部分的二氧化碳输送、火力发电厂和核电厂的工作流体方面具有当前和潜在的应用、太阳能和地热能转换系统，以及电子设备和数据中心的增强冷却。尽管 SC 流体的独特性质具有优势，但由于对异常行为的了解不足，其广泛使用受到了限制，其特点是关键区域热物理性质的大规模变化，导致热和流动振荡和其他有害现象。此外，每种物质特定的临界温度和压力范围可能不适合特定的技术需求。这项研究将解决一组重要的 SC 流体的异常行为知识空白，这将为高容量、节能和环保的流体流动和热管理系统的新技术打开大门。例如，SC条件下的天然气（SNG）可以通过陆上、地下和海底管道输送超过2000公里的距离。煤制天然气运输具有高能效，可以减少途中再压缩站的数量或完全消除它们，从而实现目前不可能的新的跨洋航线，既符合美国的国家利益，也为世界其他地方提供能源安全。与液化天然气（LNG）相比，SNG运输成本更低，对环境的影响更小，并且更加安全可靠。煤制天然气传输研究中产生的知识将有助于确定二氧化碳从海岸线传输到海底封存时的热力学状态。同样，运输 SC 氧气、氮气和其他重要工业/医用气体的方法的开发也将从这项工作中受益。这项研究的更广泛影响包括 SC 输运现象的教育机会，以及利用广泛的当前和潜在 SC 技术向代表性不足的群体进行推广，以激发对热力学的兴趣。 先前的研究表明，临界点附近的异常流体输运行为始于高于三相点的亚临界状态，并继续深入进入 SC 状态。在该研究项目中，将开发基于吉布斯自由能的热力学模型来描绘异常状态的温度-压力边界并表征高阶相变。它将应用于一系列自然/工业上重要的 SC 流体，包括水、二氧化碳、甲烷、氩气和氮气。该分析将确定超临界流体（包括超临界天然气 (SNG)）无需再压缩即可长距离运输的安全条件。 SNG 传输的全部潜力将通过开发 SC 热传输的一维计算模型来量化，并考虑传输特性变化和可压缩性、环境热条件、焦耳-汤姆逊现象和管道的热阻。将开发一个三维模型来检查入口和出口区域的流动和热行为以及周围环境温度变化的影响。热力学模型还将用于设计定制的 SC 流体混合物，以实现有效的热管理。拟议的研究包括计划制造用于 SC 流体流动和热分析的实验装置，以生成与 SC 流体特性相关的数据，检查模型验证的参数效应，并探索增强传热的方法。该奖项反映了 NSF 的法定使命，并已被通过使用基金会的智力优点和更广泛的影响审查标准进行评估，认为值得支持。