Mass Transfer and Transport Processes in Two-Phase Flow

该方案继续成功地进行了早期NSF支持的两相流输送过程的研究。总体目标是了解分子物种的湍流传输如何与拉格朗日统计有关，了解密度不同于其悬浮流体的粒子、液滴和气泡的湍流传输，了解固/液或气/液边界处质量的湍流传输如何与界面附近的流体力学因素有关，并了解空气在液体表面上流动引起的非线性波动。提出了五个项目：(1)计算机研究，它将拉格朗日和欧拉描述的湍流输送联系起来，并提供关于分子扩散率在减弱湍流输送中的作用的信息；(2)液滴、颗粒和气泡湍流输运的光学研究：(3)分层流中波动对气体吸收的影响：(4)气液分层流中的有限振幅波；(5)固-液边界上的湍流传质。这项工作的重要方面是，将进行实验室和超级计算机的联合实验，并将使用新开发的光学技术来研究颗粒的拉格朗日湍流特性，水滴和气泡，最后，这项研究最直接的结果之一将是应用于开发改进的管道中气体/液体流动的设计方程。选择该系统来研究气体吸收在许多工艺问题中具有重要的实际意义。然而，地球物理学家也感兴趣，因为环境水域表面的转移是许多物质的地球物理和自然生物化学循环的一个重要阶段。这解释了化学家、地球物理学家、土木工程师、机械工程师和环保主义者对它的广泛兴趣。

The program outlined continues successful earlier NSF supported research in transport process in two phase flow. The general objectives are to understand how turbulent transport of molecular species is related to Lagrangian statistics, to understand the turbulent transport of particles, droplets and bubbles that have a density different from the fluid in which they are suspended, to understand how the turbulent transport of mass at a solid/liquid or a gas/liquid boundary is related to fluid mechanical factors close to the interface, and to understand non-linear waves caused by air flow over a liquid surface. Five projects are proposed: (1) Computer studies that relate the Lagrangian and Eulerian descriptions of turbulent transport, and that provide information on the role of molecular diffusivity in diminishing turbulent transport; (2) Optical studies on the turbulent transport of drops, particles and bubbles; (3) Influence of waves on gas absorption in stratified flows; (4) Finite amplitude waves in gas-liquid stratified flows; (5) Turbulent mass transfer at a solid- liquid boundary. Important aspects of this work are that combined laboratory and supercomputer experiments will be conducted and that newly developed optical techniques will be used to study Lagrangian turbulence characteristics of particles, drops and bubbles and finally, one of the most immediate consequences to be derived from this study will be the application leading to development of improved design equations for gas/liquid flow in pipelines. The system chosen to study gas absorption is of practical importance in many process problems. However, it is also of interest to geophysicists, since the transfer across the surface of environmental waters is an important phase of the geophysical and natural biochemical cycles of numerous substances. This explains the widespread interest in it by chemists, geophysicists, civil engineers, mechanical engineers, and environmentalists.