CAREER: Near-Critical Heat Transfer

职业：近临界传热

• 批准号: 2235356
• 负责人: Brian Fronk
• 金额: $ 52.8万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-15 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2235356&HistoricalAwards=false
• 关键词: CAREER; Near; Critical; Heat; Transfer

At high temperatures and pressures, fluids can exist above a critical point where they can transition between “liquid-like” and “gas-like” properties without undergoing a phase change (such as the formation of bubbles or droplets). Recently, supercritical fluids have gained significant interest as working fluids in highly efficient engines, advanced aerospace applications, and electronics cooling. Supercritical fluids near the critical point have unique thermophysical properties that often provide enhanced heat transfer, but these properties can also lead to damaging flow instabilities and degraded heat transfer during certain operating conditions. The cause and control of these damaging near-critical degradations and oscillations are not well understood. This project will use a novel experimental approach to understand the physical phenomena that govern the heat transfer properties of near-critical fluids in order to predict and control their potentially damaging effects. In addition to the research objectives, this work will be linked with the development of a unique educational program dedicated to developing globally competent engineers prepared to bring supercritical technology to the market.Specifically, this research will use fiber optic sensors to measure transient convective heat transfer of supercritical fluids, and use the data to develop transient models of conjugate heat transfer in tailored, non-homogenous, heat exchanger substrates. This proposed work will provide fundamental insights on the relationship between buoyancy, flow acceleration, and varying thermophysical properties on the unsteady convective heat transfer coefficient of supercritical fluids, and new information on the evolution of high- and low-frequency flow oscillations during transients of supercritical fluids. Established theory and models developed for steady state conditions will be evaluated using experiments more representative of actual supercritical system operation. Data will be used to guide the modeling of conjugate effects in non-homogeneous substrates, laying the groundwork for components fabricated through new manufacturing techniques. Finally, the demonstration of the fiber optic instruments for distributed high accuracy heat transfer experiments is of value to the broader thermal transport community.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.

在高温和压力下，烟道可以在临界点上方存在，使它们可以在“液体状”和“类似气体”特性之间过渡而不经历相变（例如气泡或液滴的形成）。最近，随着高效发动机，晚期航空应用和电子冷却的工作流体，超临界流体引起了人们的兴趣。临界点附近的超临界流体具有独特的热物理特性，通常会提供增强的传热，但是这些特性也可以导致损害流动不稳定性和在某些工作条件下降解的热传递。这些破坏性临界降解和振荡的原因和控制尚不清楚。该项目将使用一种新型的实验方法来了解控制近临界流体的传热特性的物理现象，以预测和控制其潜在的破坏。效果。除研究目标外，这项工作还将与一个独特的教育计划相关联，该计划致力于开发全球能力的工程师，准备将超临界技术带到市场上。特别是，该研究将使用光纤传感器来测量超临界流体的瞬态对流热传递，并使用尾式传热的偶然热传递的瞬时模型，并使用量身定型的瞬时模型。拟议的工作将提供有关浮力，流动加速度以及超临界流体对流传热系数的浮力，流动加速和不同嗜热特性之间关系的基本见解，以及有关超临界流体过渡过程中高频率流动振荡的新信息。为稳态条件开发的既定理论和模型将使用更具实际超临界系统操作的实验来评估。数据将用于指导非同质底物中共轭效应的建模，从而为通过新制造技术制造的组件奠定了基础。最后，用于分布式高精度传热实验的光纤仪器的演示对更广泛的热运输社区具有价值。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响来审查标准，被视为通过评估来获得的支持。