SBIR Phase I: Large Eddy Simulations (LES) of Gas-Particle Flows

9861045这项小型企业创新研究第一阶段计划将展示大涡模拟(LES)作为预测气固两相流动现象的可行计算工具的可行性。目前的湍流模型使用许多特殊程序来表示湍流起伏以及由这些起伏引起的粒子传输。LES通过计算占主导地位的非定常大尺度湍流，消除了这种经验主义。与直接模拟不同，它允许以真实的雷诺数和合理的成本进行计算。我们建议将这一技术扩展到包括气固两相流动。在第一阶段，我们将仔细研究大涡模拟(以及流体应力和速度的亚格子尺度模拟)在颗粒扩散、混合、碰撞和沉积方面的作用。在各向同性和流道几何形状中的颗粒、湍流是被选择的两个测试案例。结果将通过将大涡模拟与先前的实验和直接数值模拟(DNS)数据进行比较来验证。在第二阶段，LES功能将扩展到贴身和非结构化网格，这是处理复杂几何图形所需的。第一阶段研究的具体目标有两个：(I)开发和验证气体-颗粒大涡模拟工具；(Ii)评估大涡模拟对扩散、沉积和碰撞等颗粒现象的影响。开发用于两相流动的LES工具将对从化学/制药工业到环境污染控制等各种领域产生深远的影响。

9861045 This small Business Innovation Research Phase I project will demonstrate the feasibility of Large Eddy Simulation (LES) as a viable computational tool for the prediction of gas-particle flow phenomena. Present-day turbulence models use many ad-hoc procedures to represent turbulence fluctuations and also particle transport by these fluctuations. LES removes this empiricism by computing the dominant, unsteady, large scale turbulence. Unlike a Direct Simulation, it allows calculation at realistic Reynolds numbers and at a reasonable cost. We propose to extend this technique to include gas-solid flows. In Phase I, we will carry out a careful study of the role of LES (and sub-grid scale modeling for both fluid stress and velocity) in the context of particulate dispersion, mixing, collision and deposition. Particulate, turbulent flows in an isotropic and channel geometry are the two test cases chosen. Results will be validated by comparing LES with prior experimental and Direct Numerical Simulation (DNS) data. In Phase II, LES capabilities will be extended to Body-Fitted and Unstructured grids, needed to tackle complex geometries. The specific objectives of the Phase I study are two-fold: (i) develop and validate Gas-Particle Large Eddy Simulation tool; and (ii) assess the impact of LES on particulate phenomena such as dispersion, deposition and collision. The development of the LES tool for two-phase flows will have a deep and far-reaching impact on a staggeringly diverse list of areas ranging from chemical/pharmaceutical industry to environmental pollution control.