Advanced Laser Diagnostics Investigating the Fluid Mechanics of Primary Breakup

先进激光诊断研究初级破裂的流体力学

• 批准号: 2879517
• 金额: --
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2879517
• 关键词: Advanced; Laser; Diagnostics; Investigating; Fluid

Spray systems are widely used in various industries, from fuel injection to pharmaceuticals, and improving their efficiency requires a deeper understanding of the primary breakup process. When a liquid core exits a nozzle, it breaks up into larger, primary drops, which then further divide into smaller droplets in a process called primary breakup. However, this mechanism is the least well-understood area of spray systems, and current numerical models have to rely on significant simplifications. The lack of knowledge about primary breakup is largely attributed to insufficient experimental data of sprays at higher Reynolds (Re) and Weber (We) numbers, this is due to the high optical density in the near-field region of a spray where this mechanism occurs. Thus, making imaging the liquid-gas interfaces (LGIs) at primary breakup difficult. To address this challenge, this PhD project aims to use state-of-the-art laser diagnostic tools, specifically two-photon light-induced fluorescence (2p-LIF) and ballistic imaging. Both ballistic imaging and 2p-LIF have been successfully employed to visualise high optical density regions The efficacy of breakup can be determined by resolving the forces acting on primary drops, which can be achieved using wavelet-based optical flow (wOF) techniques. The objective of this project is to develop an accurate wOF platform to be used with advanced laser diagnostic tools to determine the velocity and acceleration components at LGIs of the primary drops. These sprays will be generated from various isolated breakup mechanisms, including shear, turbulence, and cavitation, using a specially designed spray facility. The facility will flow liquid through custom-designed nozzles at different injection pressures and will be capable of providing a wide variety of Re, We, and cavitation (Ca) numbers. The PhD project comprises three sections, with the first two laying the groundwork for the third. Firstly, the development of a wOF platform to accurately estimate the velocity and acceleration of atomising sprays will be undertaken, using synthetic data from direct numerical simulation of atomising spray databases supplied by partners at RWTH Aachen University. Secondly, a spray facility will be designed to isolate the various breakup mechanisms highlighted earlier, with various liquids and nozzle geometries. Finally, the spray facility will be used to produce mildly atomising to highly atomising sprays for each breakup configuration, visualising the primary breakup process using 2p-LIF or ballistic imaging and coupled with the wOF platform developed to resolve the velocity and acceleration components to determine the efficacy of each breakup mechanism. The project aims to address the challenge of insufficient experimental data of the primary breakup of sprays at higher Reynolds and Weber numbers, providing new insights and data for the wider spray community to further aid in the modelling of spray systems. The data from the fundamental spray facility will serve as a basis of understanding for further research in the PRIME project proposed by Dr Brian Peterson.

从燃料注入到药品，喷雾系统广泛用于各种行业，并且提高其效率需要更深入地了解主要分手过程。当液态芯出口喷嘴时，它会分解为较大的主滴，然后在称为主要分裂的过程中进一步分为较小的液滴。但是，这种机制是喷雾系统最不受欢迎的领域，当前的数值模型必须依靠重大的简化。缺乏有关主要分手的知识在很大程度上归因于较高雷诺（RE）和韦伯（Weber（Weber）数字的喷雾剂的实验数据不足，这是由于这种机制发生这种机制的近场区域的高光密度所致。因此，使初级分解的液态气界面（LGI）变得困难。为了应对这一挑战，该博士项目旨在使用最新的激光诊断工具，特别是两光子光诱导的荧光（2P-LIF）和弹道成像。弹道成像和2p-lif均已成功地用于可视化高光密度区域，可以通过解决作​​用于初级滴的力来确定破裂的功效，这可以使用基于小波的光流（WOF）技术来实现。该项目的目的是开发一个准确的WOF平台，可与高级激光诊断工具一起使用，以确定主要滴剂LGIS处的速度和加速度组件。这些喷雾剂将使用特殊设计的喷雾设施从各种孤立的分解机制（包括剪切，湍流和气蚀）产生。该设施将在不同的注入压力下通过定制设计的喷嘴流动液体，并能够提供各种各样的RE，我们和空化（CA）数字。博士项目包括三个部分，前两个部分为第三部分奠定了基础。首先，将开发WOF平台，以准确估计雾化喷雾的速度和加速度，并使用来自RWTH AACHEN UNIXPYSER PARTNECS提供的雾化喷雾数据库的直接数值模拟的合成数据进行。其次，将设计一个喷雾设施，以隔离前面突出显示的各种分解机制，并具有各种液体和喷嘴几何形状。最后，喷雾设施将用于生产每种分解配置的轻度雾化至高度雾化的喷雾剂，使用2p-lif或弹道成像可视化主要的分手过程，并与WOF平台相结合以解决速度和加速组件以确定速度和加速度组件每个分手机制的功效。该项目旨在应对较高雷诺和韦伯数字的主要喷雾剂主要分裂实验数据的挑战，为更广泛的喷雾社区提供新的见解和数据，以进一步帮助喷雾系统的建模。来自基本喷雾设施的数据将是理解Brian Peterson博士提出的主要项目的理解的基础。