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

9861045 这个小企业创新研究第一阶段项目将证明大涡模拟（LES）作为预测气粒两相流现象的可行计算工具的可行性。现今的湍流模型使用许多特别的程序来表示湍流波动以及由这些波动引起的粒子输运。LES通过计算占主导地位的非定常大尺度湍流来消除这种湍流。与直接模拟不同，它允许以合理的成本在真实的雷诺数下进行计算。我们建议将这种技术扩展到包括气固两相流。在第一阶段，我们将进行一个仔细的研究LES（和亚网格尺度模拟流体应力和速度）的颗粒分散，混合，碰撞和沉积的背景下的作用。颗粒，湍流在各向同性和通道的几何形状是两个测试情况下选择。通过将LES与先前的实验和直接数值模拟（DNS）数据进行比较，验证结果。在第二阶段，LES功能将扩展到身体拟合和非结构化网格，需要处理复杂的几何形状。 第一阶段研究的具体目标有两个方面：（一）开发和验证气粒大涡模拟工具;（二）评估LES对分散、沉积和碰撞等颗粒现象的影响。 两相流LES工具的开发将对从化学/制药工业到环境污染控制的各种领域产生深刻而深远的影响。

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.