Direct Numerical Simulation of Fully Resolved Vaporizing Droplets in a Turbulent Flow

该奖项促进了使用大型新计算资源Blue Waters的科学研究，该资源计划于2012年部署在伊利诺伊大学。它提供差旅资金，以支持主要调查人员、Blue Waters项目团队和供应商技术团队之间的技术协调。拟议的数值研究的目标是加强对湍流中液滴蒸发和混合过程的了解。数值研究采用直接数值模拟方法研究了自由运动的汽化液滴与各向同性湍流之间的双向相互作用。液滴将在3D空间和时间内完全分解，即不被视为点粒子，并且湍流运动的所有尺度都被分解到最小的相关长度和时间尺度(柯尔莫戈罗夫尺度)。重点将放在蒸发液滴和周围湍流气体之间的质量、动量和能量的双向交换上。在未来的研究中，湍流将被假设为各向同性作为第一步，然后再考虑湍流剪切流。拟议的研究结果将潜在地影响能源的有效利用。产生这种影响的原因是，汽化速率是燃料液滴燃烧的主要控制机制，液体燃料是所有运输方式最重要的能源，并将在可预见的未来保持不变。了解湍流中汽化和混合过程的物理细节是了解化学反应过程和最终控制/优化能量转换过程的基本前提。国际学生联合会在研究领域和研究与教学相结合方面取得了成就，包括与本科生和理科代表性不足的学生进行了接触。

This award facilitates scientific research using the large new computational resource named Blue Waters scheduled to be deployed at the University of Illinois in 2012. It provides travel funds to support technical coordination between the principal investigators, the Blue Waters project team and vendor technical team.The objective of the proposed numerical study is to enhance the understanding of liquid droplet vaporization and mixing processes in a turbulent flow. The numerical study employs direct numerical simulations (DNS) to examine the two-way interactions between freely-moving vaporizing droplets and isotropic turbulence. The droplets will be fully resolved in 3D space and time, i.e. not treated as point particles, and all the scales of the turbulent motion are resolved down to the smallest relevant length- and time-scales (the Kolmogorov scales). The emphasis will be on the two-way exchange of mass, momentum and energy between the vaporizing droplets and the surrounding turbulent gas. The turbulence will be assumed isotropic as a first step before considering turbulent shear flows in future studies.The results of the proposed study will potentially impact efficient utilization of energy. This impact stems from the fact that the vaporization rate is the main controlling mechanism of fuel droplet combustion and that liquid fuels are the most important source of energy for all modes of transportation and will remain as such for the foreseeable future. Understanding the physical details of the vaporization and mixing processes in a turbulent flow is an essential prerequisite to understanding the chemical reaction process and the eventual control/optimization of the energy conversion process. The PI has a record of accomplishment in the field of study and in combining research and teaching, including outreach to undergraduate students and underrepresented students in the sciences.