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室的效率。在超音速推进系统中，燃油喷射过程的细节很难在实验中测量。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。拟议的计算框架将允许研究人员在超级计算机上进行模拟，产生比实验所能提供的更详细的数据。该项目开发的仿真程序将是开源的，其他研究人员可以在此基础上开发新的仿真能力。该项目的成果将对超音速推进的学术界和产业界都有所裨益。除了研究项目，还将为贝勒的梅伯恩博物馆开发一个关于燃油喷射的展览。本次展览将利用本项目的成果向所有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产生的复杂拓扑变化，将发展一种适用于可压缩流动的质量和动量守恒的流体体积方法。将采用高阶激波捕捉方法来解决激波和激波-界面相互作用。采用高度函数法计算界面曲率，并将平衡力表面张力计算推广到可压缩流动。上述数值方法也将推广到四叉树/八叉树数据结构，以允许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，即使使用了大量的精化级别，并行性能也将保持出色。四种不同的亚音速和超音速液体喷射破碎实验将被模拟，并与实验测量结果进行比较，以验证建议的模拟框架的预测能力。该奖项反映了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。

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.