Collaborative Research: High-speed Imaging Guided Large Eddy Simulation (LES) Model Development for Turbulent Flames

合作研究：湍流火焰的高速成像引导大涡模拟模型开发提议的研究工作是为通常嵌入湍流中的实际火焰开发计算机模型，例如飞机发动机和发电厂中的火焰。这里开发的改进的建模工具可以扩展到许多其他领域，如烟灰建模、火灾模拟、地球物理流体动力学和环境科学。主要研究人员将进一步继续他们的实践，指导一个多样化的高中和本科研究人员群体，以吸引和准备他们在科学和工程研究生的职业生涯。全面了解火焰稳定对于未来电力、推进和运输系统的清洁和高效燃烧至关重要。在这种情况下，大涡模拟（LES）方法为火焰稳定和相关燃烧动力学建模提供了合适的框架。然而，目前的LES模型远非理想，并且引入了可能改变模拟中时间动态的简化。在这里，LES建模方法将被重新表述，以引入时间统计和非平衡耗散率。同时，高速成像数据将与非常大规模的直接数值模拟（DNS）相结合，以验证统计数据和LES模型中的中心假设。一个行业合作伙伴将与研究团队合作，以确保模型和实验数据的相关性。教育和外联部分将有助于将新知识和技术转移到课堂和工业。所提出的工作的智力价值在于提供了对火焰稳定的全面理解，超越了典型的一点，集合统计平均，并将使开发一个强大的和预测的计算模型成为可能。它将利用基于高速激光成像和DNS的最新进展来扩大LES建模方法的适用性范围。这里开发的CFD模型和实验数据将提供给燃气轮机行业和成熟的湍流非预混火焰（TNF）国际工作组。

1403969/1403901Meyer/RamanCollaborative Research: High Speed Imaging Guided Large Eddy Simulation Model Development for Turbulent FlamesThe proposed research effort is to develop computer models for practical flames that are usually embedded in turbulent flows such as those in aircraft engines and power generation plants. The improved modeling tools developed here can be extended for use in many other fields such as soot modeling, fire simulations, geophysical fluid dynamics, and environmental sciences. The principal investigators will furthermore continue their practice of mentoring a diverse group of high-school and undergraduate researchers to attract and prepare them for graduate careers in science and engineering.A comprehensive understanding of flame stabilization is critical for clean and efficient combustion in future power, propulsion, and transportation systems. In this context, the large eddy simulation (LES) methodology provides a suitable framework for modeling flame stabilization and related combustion dynamics. However, current LES models are far from ideal and introduce simplifications that potentially alter the temporal dynamics in the simulations. Here, the LES modeling approach will be reformulated to introduce temporal statistics and a non-equilibrium dissipation rate. Simultaneously, high-speed imaging data will be combined with very large-scale direct numerical simulations (DNS) to validate central assumptions in the statistical data and LES model. An industry partner will collaborate with the research team to ensure the relevance of models and experimental data. Educational and outreach components will aid the transfer of new knowledge and technologies to the classroom and industry. The intellectual merit of the proposed work lies in providing a comprehensive understanding of flame stabilization beyond typical one-point, ensemble statistical averages and will enable the development of a robust and predictive computational modeling. It will take advantage of recent advances in high-speed laser-based imaging and DNS to expand the range of applicability of the LES modeling approach. The CFD models and experimental data developed here will be made accessible to the gas turbine industry and the well-established international working group on turbulent non-premixed flames (TNF).