Mass Transfer and Transport Processes in Two-Phase Flow

该计划概述了早期 NSF 支持的两相流传输过程研究的成功。 总体目标是了解分子种类的湍流传输如何与拉格朗日统计相关，了解密度与其悬浮的流体不同的颗粒、液滴和气泡的湍流传输，了解固/液或气/液边界处的质量湍流传输如何与靠近界面的流体力学因素相关，并了解由液体表面上的气流引起的非线性波。 提出了五个项目：（1）计算机研究，将湍流传输的拉格朗日和欧拉描述联系起来，并提供有关分子扩散性在减少湍流传输中的作用的信息； (2) 液滴、颗粒和气泡湍流传输的光学研究； (3) 波浪对分层流中气体吸收的影响； (4)气液分层流中的有限振幅波； (5)固液边界处的湍流传质。 这项工作的重要方面是，将进行实验室和超级计算机联合实验，并使用新开发的光学技术来研究颗粒、液滴和气泡的拉格朗日湍流特性，最后，从这项研究中得出的最直接的结果之一将是改进管道中气体/液体流动设计方程的应用。 选择用于研究气体吸收的系统在许多过程问题中具有实际重要性。 然而，地球物理学家也对此感兴趣，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化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.