EAGER: Time-Resolved Measurements and Control of Vortex Breakdown via Heat Addition

EAGER：通过加热进行涡流破坏的时间分辨测量和控制

• 批准号: 2152596
• 负责人: Anya Jones
• 金额: $ 26.6万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-15 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2152596&HistoricalAwards=false
• 关键词: EAGER; Time; Resolved; Measurements; Control

This project was inspired by the discovery and ongoing study of the blue whirl, an apparent breakdown mode of a fire whirl in which it unexpectedly transitions to a small and seemingly benign blue flame. The blue whirl produces no soot and minimal pollutants, suggesting optimal burning and a potential source of clean energy. Creating a blue whirl without having to pass through the fire whirl state would enable a safe and clean form of hydrocarbon combustion that could be used in combustors, for propulsion, or for controlled burns (e.g., oil spill clean-up). More broadly, because vortex breakdown occurs in a wide variety of applications, a better understanding and ability to control and predict its dynamics has broad implications for many fluid dynamics systems affected by this instability. Controlling vortex breakdown would enable higher force production and enhance aerodynamic stability on wings and blades ranging from small-scale micro air vehicles to large-scale wind turbines, as well as more robust pump operation in cooling and emergency operations. This project aims to characterize and quantify the process of vortex breakdown in an incompressible non-reacting flow, and to identify mechanisms by which breakdown might be controlled via a new type of experiment wherein energy (in the form of heat) is introduced into the core of a vortex flow. The objective of this project is to experimentally demonstrate the effect of heat injection on vortex breakdown in a non-reacting incompressible flow, and to evaluate the parameter space over which heat addition has a measurable effect on the breakdown process and final state of the flow. A new type of vortex breakdown experiment will be developed to enable time-resolved velocity field measurements in a swirling flow with variable temperature (and thereby density) gradients. Complementary numerical simulations (performed by collaborators X. Zhang and E. Oran) will provide guidance in the development of the experimental facility and test matrix, and will make it possible to explore regions of the parameter space not easily achieved in the laboratory. Results from these experiments will include quantitative time-resolved measurements of the changes in flow structure during the process of vortex breakdown, with and without heat injection. The proposed experiments are expected to provide new physical insight into the process and mechanisms of vortex breakdown to inform theories and scaling laws, allowing for a generalization of the results gained here towards new methods of vortex control.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.

该项目的灵感来自对蓝旋转的发现和正在进行的研究，这是一种明显的崩溃模式，它出乎意料地将其出乎意料地转变为一个小而良性的蓝色火焰。蓝色旋转不会产生烟灰和最小污染物，表明最佳燃烧和潜在的清洁能源。创建一个蓝色的旋转而不必通过火旋转状态将使可以在燃烧器，推进或受控燃烧（例如，溢油清理）中使用安全干净的碳氢化合物燃烧形式。更广泛地说，由于涡流分解发生在各种应用中，因此更好地理解和控制和预测其动力学的能力对受这种不稳定性影响的许多流体动力学系统具有广泛的影响。控制涡流分解将使较高的力量产生并增强机翼和叶片的空气动力学稳定性，从小规模的微型航空车到大型风力涡轮机，以及在冷却和紧急操作中更强大的泵操作。该项目旨在表征和量化不可压缩的非反应流中涡流分解的过程，并确定可以通过新型实验控制分解的机制，其中将能量（以热量形式）引入涡流流的核心。该项目的目的是在非反应不可压缩的流中实验证明热注入对涡旋分解的影响，并评估参数空间，在该参数空间中，加热对流动的分解过程和最终状态具有可测量的影响。将开发一种新型的涡流分解实验，以在旋转温度（及其密度）梯度变化的旋流流中实现时间分辨的速度场测量。互补的数值模拟（由合作者X. Zhang和E. Oran执行）将为实验设施和测试矩阵的开发提供指导，并将使探索实验室中不容易实现的参数空间区域成为可能。这些实验的结果将包括定量时间分辨的测量，这些测量值对涡流分解过程中流动结构的变化以及有或不进行热注射。预计拟议的实验将提供有关涡旋分解的过程和机制的新物理见解，以告知理论和扩展法，从而允许在此获得的结果概括为涡旋控制的新方法。该奖项反映了NSF的法定任务，并通过使用该基金会的知识优点和广泛的criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia criperia rection the Andimation奖。