EAGER: Establishment of a High-Fidelity Simulation Infrastructure for Fuel Injection and Combustion in Supersonic Flows

燃料液滴的特性直接影响燃烧器的效率。在超声速推进系统中，燃油喷射过程的细节在实验中很难测量。本文将开发一个用于模拟超音速推进系统中液体燃料动力学的高保真计算框架。所提出的计算机程序可用于改进超音速飞机和火箭的高燃油效率和低污染物排放的喷油器设计。提出的计算框架将允许研究人员在超级计算机上进行模拟，从而产生比实验所能提供的更详细的数据。在这个项目中开发的模拟程序将是开源的，其他研究人员可以在此基础上开发新的模拟功能。该项目的成果将有利于超音速推进的学术界和工业界。随着研究项目，一个关于燃油喷射的展览将为贝勒的梅伯恩博物馆开发。本次展览将利用该项目的成果向各年龄段的观众介绍燃油喷射技术。为了准确地捕捉气液界面和由于破裂而引起的复杂拓扑变化，将开发一种可压缩流动的质量和动量守恒的流体体积方法。高阶激波捕获方法将被纳入解决激波和激波界面的相互作用。将采用高度函数法计算界面曲率，并将平衡力表面张力计算扩展到可压缩流动。上述数值方法也将推广到四叉树/八叉树数据结构中，以便在用户定义的区域中进行自适应网格细化。代码的并行化将通过树分解方法来完成，而不是传统的域分解。因此，即使使用了大量的细化级别，并行性能仍将保持优异。将模拟亚音速和超音速条件下液体射流破裂的四种不同实验，并与实验测量结果进行比较，以验证所提出的模拟框架的预测能力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The characteristics of the fuel droplets have a direct impact on the efficiency of a combustor. In supersonic propulsion systems, the details of the fuel injection process are difficult to measure in experiments. A high-fidelity computational framework for simulating liquid fuel dynamics in supersonic propulsion systems will be developed. The proposed computer program can be used to improve injector designs for high fuel efficiency and low pollutant emissions in supersonic aircrafts and rockets. The proposed computational framework will allow researchers to perform simulations on supercomputers that produce more detailed data than experiments can provide. The simulation program developed in this project will be open-source, based on which other researchers can develop new simulation capabilities. The outcome of this project will benefit both academia and industry of supersonic propulsion. Along with the research project, an exhibition on fuel injection will be developed for Baylor's Mayborn Museum. This exhibition will use the results obtained in this project to introduce fuel injection technologies to audiences of all ages.To accurately capture the gas-liquid interface and the complex topology changes due to breakup, a mass- and momentum-conserving volume-of- fluid method for compressible flows will be developed. High-order shock-capturing methods will be incorporated to resolve shock waves and shock-interface interactions. The Height-Function method will be used to calculate the interface curvature, and the balanced-force surface tension calculation will be extended to compressible flows. The above numerical methods will also be generalized for the quad/octree data structure to allow adaptive mesh refinement in user-defined regions. The parallelization of the code will be done through a tree decomposition approach instead of the conventional domain decomposition. As a result, the parallel performance will remain excellent even if a large number of refinement levels are used. Four different experiments of liquid jet breakups in subsonic and supersonic regimes will be simulated and compared to experimental measurements to validate the predictive capability of the proposed simulation framework.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.