Supercritical fuel jets - resolving controversy

超临界燃料喷气机 - 解决争议

• 批准号: EP/P011438/1
• 负责人: Mark Linne
• 金额: $ 45.13万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP011438%2F1
• 关键词: Supercritical; fuel; jets; resolving; controversy

New high efficiency engine combustion modes hold the promise to significantly reduce the contribution of transport vehicles to climate change. All of these modes rely upon direct injection of fuel into the combustion chamber, and so fuel/air mixture preparation is a controlling process in terms of engine efficiency (i.e. reduced CO2 production) and pollutant emissions (including soot, another contributor to climate change). As these new combustion modes push to higher pressure and temperature, it would appear that the fuel jets probably undergo a thermodynamic change, becoming supercritical at the edges of the jet. If that were true, it would completely change our current understanding of fuel/air mixture preparation, and that would have a significant effect on engine performance and design. At this time several theory groups are in disagreement on whether or not this change happens, and if it does how best to understand it. This project will resolve those disagreements, and it will lead to the understanding required to adapt both fuel injectors and engines to this potential new reality.Aside from the motor industry, supercritical mixing is important to the pharmaceutical, food processing, catalyst production, and other nanomaterials industries, and our goal is to team with researchers in these areas as well.This project has four main parts. A specialized, optically-accessible cell will be designed and built based on a successful design under operation at the Technical University of Darmstadt. A laminar liquid jet (with clear access to the fluid/gas interface) will flow down through this chamber, which can be set to various pressures and temperatures below and above the liquid critical point. A line-Raman scattering instrument will be developed in order to characterize the chemical composition of the flowfield as a function of time and position. Next, laser induced thermal acoustics (LITA) will be developed. LITA will be used to measure the sound speed as a function of position and time as conditions are varied. The sound speed reaches a minimum at the critical point, and increases very steeply as pressure and temperature go above the critical point, so it can be a significant marker for thermodynamic states. Finally, Förster resonance energy transfer (FRET) will be evaluated as a way to observe changes in the density (mean free path) as the jet approaches a supercritical state. Such a change is considered to be a distinctive marker for this state as well. This program has been designed specifically for our theory partners (City University London, Sandia National Labs, Stanford University, and University of Wisconsin), who have taken part in planning discussions for this proposal. We will thus use the experiments to provide quantitative information never before available to academia or to industry. The information will provide unambiguous, quantitative results with two aspects: 1) Industry can use them to re-think their mixture preparation strategies, while 2) theoreticians can use the results to inform and validate models. Ultimately those models will be delivered to industry.As mentioned, there are many other subject areas interested in similar problems. Once this system is operating well we will approach UK researchers working in related areas and offer this facility for collaborative research.The US Air Force Office of Scientific Research has committed to support partially this effort, with $360,000.

新型高效发动机燃烧模式有望显着减少运输车辆对气候变化的影响。所有这些模式都依赖于将燃料直接喷射到燃烧室中，因此燃料/空气混合物的制备是发动机效率（即减少二氧化碳产生）和污染物排放（包括烟尘，气候变化的另一个因素）方面的控制过程。随着这些新的燃烧模式推向更高的压力和温度，燃料射流似乎可能经历热力学变化，在射流边缘变得超临界。如果这是真的，它将彻底改变我们目前对燃油/空气混合物制备的理解，这将对发动机的性能和设计产生重大影响。目前，几个理论团体对于这种变化是否发生以及如果发生如何最好地理解它存在分歧。该项目将解决这些分歧，并将导致人们理解使燃油喷射器和发动机适应这一潜在的新现实。除了汽车行业之外，超临界混合对于制药、食品加工、催化剂生产和其他纳米材料行业也很重要，我们的目标是与这些领域的研究人员合作。该项目有四个主要部分。将根据达姆施塔特工业大学正在运行的成功设计来设计和建造一个专门的光学访问单元。层流液体射流（可以清楚地进入流体/气体界面）将向下流过该室，该室可以设置为低于和高于液体临界点的各种压力和温度。将开发线拉曼散射仪器，以表征流场的化学成分随时间和位置的变化。接下来，将开发激光诱导热声学（LITA）。 LITA 将用于测量随着条件变化而随位置和时间变化的声速。声速在临界点达到最小值，并且随着压力和温度高于临界点而急剧增加，因此它可以成为热力学状态的重要标志。最后，福斯特共振能量转移 (FRET) 将作为一种观察射流接近超临界状态时密度（平均自由程）变化的方法进行评估。这种变化也被认为是该州的一个独特标志。该计划是专门为我们的理论合作伙伴（伦敦城市大学、桑迪亚国家实验室、斯坦福大学和威斯康星大学）设计的，他们参与了该提案的规划讨论。因此，我们将利用这些实验来提供学术界或工业界以前从未获得过的定量信息。这些信息将提供两个方面的明确的定量结果：1）工业界可以使用它们重新思考其混合物制备策略，而2）理论家可以使用这些结果来告知和验证模型。最终这些模型将交付给业界。如前所述，还有许多其他主题领域对类似问题感兴趣。一旦该系统运行良好，我们将与从事相关领域工作的英国研究人员接洽，并提供该设施进行合作研究。美国空军科学研究办公室已承诺提供 360,000 美元的部分支持。

项目成果

Improving the spatial dynamic range of digital inline particle holography.

• DOI: 10.1364/ao.58.000a65
• 发表时间: 2018-12
• 期刊: Applied optics
• 影响因子: 1.9
• 作者: Z. Falgout;Yi Chen;D. Guildenbecher

Reflectivity of diffuse, transcritical interfaces

漫反射、跨临界界面的反射率

• DOI: 10.1007/s00348-022-03492-9
• 发表时间: 2022
• 期刊: Experiments in Fluids
• 影响因子: 2.4
• 作者: Yang S

High-Pressure Flows for Propulsion Applications

用于推进应用的高压流

• DOI: 10.2514/4.105814
• 发表时间: 2020
• 期刊: High-Pressure Flows for Propulsion Applications
• 作者: J. Devaney;J. Girard;M. Marino
• 通讯作者: M. Marino

A study of Novec 649TM fluid jets injected into sub-, trans-, and supercritical thermodynamic conditions using planar laser induced fluorescence and elastic light scattering diagnostics

使用平面激光诱导荧光和弹性光散射诊断研究注入亚临界、跨临界和超临界热力学条件的 Novec 649TM 流体射流

• DOI: 10.1063/5.0106473
• 发表时间: 2022
• 期刊: Physics of Fluids
• 影响因子: 4.6
• 作者: Kasapis G

Breakup of a laminar liquid jet by coaxial non-swirling and swirling air streams

同轴非旋流和旋流气流对层流液体射流的破碎

• DOI: 10.1063/5.0100456
• 发表时间: 2022
• 期刊: Physics of Fluids
• 影响因子: 4.6
• 作者: Liang Y