Acquisition of a High-Energy, Narrow Linewidth Laser for Gas-Phase Scalar Mixing Studies in Turbulent Spray Flows

0853513萨顿该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助。这是一个小的设备赠款，用于购买高能量，窄线宽，注入种子Nd：YAG激光器。该仪器将是先进的成像研究的主要组成部分，以调查在湍流喷雾流的气相标量混合。可能最著名的湍流喷雾的例子存在于实际的能量转换系统中，其中液体燃料进入氧化环境，分散，蒸发，并在反应之前与氧化剂混合。虽然这些系统由于几种物理和化学过程而变得复杂，但它们最终受到液体燃料蒸发速率以及燃料蒸气与氧化剂在最细微的物理长度尺度上混合的速率的限制。气相标量混合，而在单相湍流的深入研究，并没有被广泛研究，在多相流环境中，主要是由于缺乏可靠的实验技术，可以确定气相浓度与足够的精度。PI打算使用采购的激光器来验证一种新的实验方法，用于过滤瑞利散射（FRS）成像技术的一种新变体，以在存在液相液滴的情况下定量测量气相标量浓度。可以在不受液滴干扰的情况下导出重要的量，例如描述两个非预混流之间的混合程度的气相混合物分数和描述两个流混合的标量耗散率。这种测量对于理解描述液相蒸发和随后的汽相混合的基本物理学至关重要。此外，这些测量将提供有价值的评估和开发支持大涡模拟湍流喷雾建模。多相湍流在许多工程应用中具有重要意义，包括直接喷射式汽车发动机、液体推进剂火箭发动机、工业炉和水雾灭火系统。PI将直接支持研究生开发和实施气相标量测量技术。将尽一切努力让包括妇女和少数族裔在内的被归类为代表性不足的学生参与。

0853513SuttonThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This is small equipment grant for the acquisition of a high-energy, narrow-linewidth, injection-seeded Nd:YAG laser. This instrument will be the primary component for advanced imaging studies to investigate the gas-phase scalar mixing in turbulent spray flows. Probably the best known examples of turbulent sprays exist in practical energy conversion systems where a liquid fuel issues into an oxidizing environment, disperses, evaporates, and mixes with the oxidizer before reacting. Although these systems are complicated by several physical and chemical processes, they are ultimately limited by the rate that liquid fuel evaporates and the fuel vapor mixes with the oxidizer at the finest physical length scales. Gas-phase scalar mixing, while studied in-depth for single-phase turbulent flows, has not been studied extensively in multiphase flow environments primarily due a lack to reliable experimental techniques that can determine the gas-phase concentration with sufficient accuracy. The PI intends to use the procured laser to validate a new experimental methodology for a novel variation of the Filtered Rayleigh Scattering (FRS) imaging technique to quantitatively measure the vapor-phase scalar concentration discriminately in the presence of liquid-phase droplets. Important quantities such as the gas-phase mixture fraction, which describes the degree of mixing between two non-premixed streams, and the scalar dissipation rate, which describes the that the two streams mix, may be derived without interference from the droplets. Such measurements are crucial for understanding the fundamental physics describing the evaporation of the liquid phase and the subsequent mixing of the vapor phase. In addition, these measurements will provide valuable assessment and development support for Large-Eddy Simulation modeling of turbulent sprays. Multiphase turbulent flows are of significant interest in many engineering applications including direct-injection automotive engines, liquid-propellant rocket engines, industrial furnaces, and water-mist fire-suppression systems. A graduate student will be supported directly by the PI to develop and implement the gas-phase scalar measurement technique. Every effort will be made to include the participation of students classified as underrepresented including women and ethnic minorities.