UNS: Heat Transfer in Granular Flows: Understanding Similarities and Differences with Molecular Fluids

UNS：颗粒流中的传热：了解分子流体的异同

• 批准号: 1512630
• 负责人: Christine Hrenya
• 金额: $ 32万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1512630&HistoricalAwards=false
• 关键词: UNS; Heat; Transfer; Granular; Flows

The proposed study aims at understanding why particles in fluid might or might not enhance heat transfer for surfaces. The investigator will examine results from models and experiments to shed lights on existing conflicting work. Part of the proposed plan is to engage undergraduates and high school students in separate, small research projects aimed at the magazine Annals of Improbable Research (AIR) with an editorial board that includes several Nobel Prize winners. AIR has a tagline "research that makes people laugh and then think," designed to motivate a broader range of students to gain experience in scientific research, as well as a means for making science more accessible and exciting for the greater public. The PI proposes to develop numerical models and experimentally validate the numerical models (and the associated hypotheses) for application of granular flows in enhancing heat transfer during two-phase flows. The existing experimental results in the literature perplexedly indicates heat flux does not scaling monotonously with Peclet number. The proposed research aims at resolving such a contradiction and is thus intriguing. This work builds on recent research involving multi-phase flows but adds complex approaches involving granules with different shapes, surface roughness, slip velocities, and flow instabilities. The hypotheses to be tested are: (1) the discrepancy in existing data sets in the literature for macro-level quantities (heat transfer coefficient) can be traced to micro-level characteristics, such as surface roughness and tomography; (2) an increase in particle mobility can lead to reduced heat transfer due to reduced contact time with boundary; (3) the presence of flow instabilities may attenuate heat transfer due to increased particle mobility and thus decreased contact.

拟议的研究旨在了解为什么流体中的颗粒可能会或可能不会增强表面的传热。 研究人员将研究模型和实验的结果，以示为现有冲突工作的灯光。 拟议的计划的一部分是，与包括诺贝尔奖获得者在内的编辑委员会有关，针对不可思议的研究（AIR）杂志的单独的小型研究项目，旨在参与独立的小型研究项目（AIR）。 Air具有“使人们发笑然后思考的研究”的标语，旨在激励更广泛的学生获得科学研究的经验，以及一种使科学对更大公众更容易获得和令人兴奋的手段。 PI提议开发数值模型，并通过实验验证数值模型（以及相关的假设），以在两相流动期间在增强传热中应用颗粒流。 文献中现有的实验结果令人困惑地表明，热通量不会与小子数单调缩放。 拟议的研究旨在解决这种矛盾，因此引人入胜。 这项工作是基于涉及多相流的最新研究，但添加了涉及具有不同形状，表面粗糙度，滑动速度和流动不稳定性的颗粒的复杂方法。要测试的假设是：（1）文献中现有数据集的宏观量（传热系数）的差异可以追溯到微级特征，例如表面粗糙度和层析成像； （2）由于与边界的接触时间减少，粒子迁移率的增加会导致热传递减少； （3）流动不稳定性的存在可能会导致由于颗粒迁移率增加而导致接触减少而导致的传热。