Study of Coherent Structures of Turbulence in Flows with Wall Heat Flux in Supercritical Fluids

超临界流体壁面热通量湍流相干结构研究

• 批准号: 138578-2013
• 负责人: Yaras, Metin
• 金额: $ 1.68万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569365
• 关键词: Study; Coherent; Structures; Turbulence; Flows

Proposed advanced designs for power-generation plants with improved thermal efficiency and reduced size include configurations with supercritical working fluids, such as nuclear reactors utilizing supercritical water as the coolant for the nuclear core and Brayton cycles utilizing supercritical working fluids in a closed-cycle configuration. The success of such advanced power plants is dependent on our ability to accurately predict the rate of heat transfer in certain components of the power plant. There is experimental evidence that for certain combinations of heat and mass fluxes in supercritical fluid flows in heated channels, the measured rate of forced-convection heat transfer notably deviates from those predicted by existing correlations that are based on single-phase subcritical fluids. The proposed study aims to improve our fundamental understanding of the role of flow turbulence in these observed variations in the heat-transfer rate. The study makes use of direct numerical simulations - solution of the governing equations of fluid dynamics without any assumptions on turbulence motion - on clusters of computers supplemented by experimental measurements in a supercritical refrigerant (R134a) and supercritical water. The study includes systematic variations in parameters known to affect shear-layer turbulence, such as streamwise pressure gradient and flow Reynolds number.

为提高热效率和缩小规模而提议的发电厂先进设计包括使用超临界工质的配置，例如使用超临界水作为核芯的冷却剂的核反应堆，以及在闭合循环配置中使用超临界工质的布雷顿循环。这种先进发电厂的成功取决于我们能否准确预测发电厂某些部件的传热率。有实验证据表明，对于超临界流体在加热通道中流动的某些热流和质流组合，所测得的强迫对流换热速率与现有的基于单相亚临界流体的关联式的预测值有显著的偏差。 这项拟议的研究旨在提高我们对流动湍流在这些观察到的传热率变化中所起的作用的基本理解。这项研究利用了在计算机集群上的直接数值模拟--求解流体动力学的控制方程，而不对湍流运动作任何假设--并辅之以超临界制冷剂(R134a)和超临界水的实验测量。这项研究包括已知的影响剪切层湍流的参数的系统变化，如流向压力梯度和流动雷诺数。