CAREER: Enhancing Shock-Driven Turbulent Mixing using Multiphase Hydrodynamics

多相混合在日常生活中很常见，例如将糖粒搅拌成咖啡。然而，两个独立的相(在本例中是固体糖和液体咖啡)之间的相互作用导致了复杂的混合过程，这种混合过程发生在大尺度和小尺度上。在许多工程和自然应用中，这种混合是由冲击波引起的，导致快速混合和相变。了解多相混合过程可以帮助科学家更好地了解超新星和火山喷发等自然问题，并改进工程应用，例如用于生产电力的蒸汽涡轮机，以及用于军用飞机的先进喷气发动机设计。这项工作将使用一个简化的实验来研究颗粒特性(如大小)在激波驱动混合中的作用。实验测量将用于验证多相混合的新模型，并确保计算机模拟的准确性。这些模拟可以用来研究多相混合中的其他问题。此外，这项工作将产生更广泛的影响，使工科学生成为他们职业生涯和社区的领导者。这将通过几项举措来实现，包括开设一堂关于液体混合的高中课堂课程；从代表性不足的群体中招募和指导学生；以及组织一次国家安全研究研讨会，以帮助学生和教职员工将研究应用于国防。这一职业项目的研究目标是测试激波驱动的湍流混合可以通过包含规定的多相成分来增强的假设。该项目将采用实验和模拟相结合的方法发展一种新的理论，建立强加速多相蒸发混合中小尺度颗粒驱动机制和大尺度流体力学机制之间的关系。实验将在皮？S激波管装置中进行，在那里将进行流体动力和粒子混合的测量。模拟将使用之前发展的PI？S粒子模型进行，并通过实验测量进行验证。这项工作将分为三个任务：1)确定颗粒速度松弛时间对流体动力混合的影响；2)确定流体动力混合对颗粒蒸发的影响；以及3)确定二次加速产生的水蒸气对混合的影响。使用这些测量，模拟粒子模型将得到验证，并用于探索更多实验上无法达到的测量和更广泛的参数空间。实验和模拟结果都将被用来开发和测试新的理论，以预测流体动力和湍流状态下的气体和蒸汽/颗粒混合。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Multiphase mixing is common in everyday life, such as the stirring of sugar granules into coffee. Yet the interactions between the two separate phases (solid sugar and liquid coffee in this example) results in complex mixing processes that occur at both large and small length scales. In many engineering and natural applications, this mixing is induced by shock waves, resulting in rapid mixing and phase change. Understanding multiphase mixing processes can help scientists better understand natural problems like supernovae and volcanic eruptions, and improve engineering applications, such as steam turbines used to produce electric power and advanced jet engine designs used for military aircraft. This work will use a simplified experiment to study the role of particle characteristics (like size) in shock-driven mixing. Experimental measurements will be used to validate new models for multiphase mixing and to ensure the accuracy of computer simulations. These simulations can then be used to study additional problems in multiphase mixing. Additionally, this work will have a broader impact by preparing engineering students to be leaders in their careers and communities. This will be accomplished through several initiatives, including developing a high school classroom lesson on fluids mixing; recruiting and mentoring students from underrepresented groups; and organizing a national security research symposium to help students and faculty apply research toward national defense. The research objective of this CAREER project is to test the hypothesis that shock-driven turbulent mixing can be enhanced by the inclusion of a prescribed multiphase component. This project will use an integrated experimental and simulation approach to develop a new theory establishing the relationship between small-scale particle-driven mechanisms and large-scale hydrodynamic mechanisms in strongly accelerated multiphase mixing with evaporation. Experiments will be performed in the PI?s shock tube facility where measurements of hydrodynamic and particle mixing will be made. Simulations will be performed using the PI?s previously developed particle models, validated by the experimental measurements. The work will be broken into three tasks: 1) Determine the effect of particle velocity relaxation time on hydrodynamic mixing; 2) Determine the effect of hydrodynamic mixing on particle evaporation; and 3) Determine the effect of vapor production on mixing from secondary accelerations. Using these measurements, the simulation particle models will be validated and used to explore additional experimentally inaccessible measures and a wider parameter space. Both experimental and simulation results will be used to develop and test new theory to predict gas and vapor/particle mixing in hydrodynamic and turbulent regimes.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.