Investigation on gas-liquid-solid three phase flow coupled with meso-scale particle-bubble interactions, particle-liquid turbulence and bubble induced turbulence in bubble column reactors

鼓泡塔反应器中气-液-固三相流与细观颗粒-气泡相互作用、颗粒-液湍流和气泡诱导湍流耦合的研究

• 批准号: 391978046
• 负责人: Professor Dr.-Ing. Martin Sommerfeld
• 金额: --
• 依托单位: Institut für Verfahrenstechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/391978046?language=en
• 关键词: Investigation; gas; liquid; solid; three

This project aims to investigate the multi-phase flow behaviours and the mechanisms of interactions among phases in gas-liquid-solid three-phase bubble column reactors. The research methodologies will include the combination of theoretical modelling, numerical simulation and experimental work. Numerical calculations will be done concurrently using a multi-fluid approach in combination with a population balance for the three phases and a LES-Euler/Lagrange method. Both approaches have to be extended for allowing three-phase bubble column simulations considering all relevant transport mechanisms. This includes first of all the consideration of all forces important for correctly describing bubble and particle motion. Models will be developed for the meso-scale interactions between particles and bubbles, bubble induced turbulence and particle modulated liquid turbulence in bubble column reactors. Hence the proposed project includes the following core tasks, each combined with a detailed validation and cross-comparison of both approaches:(1) Modelling particle-bubble interactions including a possible sticking probability by adhesion forces. This model will be based on the stochastic collision model, which includes hydrodynamic interactions. An additional resistance term for both phases will be introduced in order to describe particles being dragged by bubbles and vice versa. These model developments will be supported by Lattice-Boltzmann simulations where bubbles are resolved and particles are treated as point masses.(2) Develop a novel bubble coalescence and breakup kernel that takes into account the effects of bubble induced turbulence, modulation on liquid phase turbulence by solid particles, and the impact of modified turbulence on bubble coalescence and breakup. The proposed model will be implemented by employing two bubble group population balance models.(3) To develop a liquid-phase sub-grid model that considers the scale and concentration effects of liquid phase turbulence modulation by bubbles and solid particles, which will then be coupled with the two bubble group population balance models to perform three-phase large eddy simulation. In addition sub-grid turbulence closures will be developed for application in the frame of LES-Euler/Lagrange simulations.(4) Adaptation of PIV and ECVT techniques to experimentally obtain the fluid dynamic parameters and characteristics of phase distribution in gas-liquid-solid three-phase bubble column reactors, especially the liquid phase turbulence power spectra. The experimental data will be used to validate the large eddy simulation of three-phase bubble column reactor, as well as two-fluid and Euler/Lagrange approaches and study the fundamental interactions of gas-liquid-solid three phases. The project will reveal the meso-scale turbulence structures due to particles and bubbles in the three-phase bubble column reactors and the coupling mechanisms of turbulence modulation.

本计画旨在探讨气-液-固三相鼓泡床反应器内多相流动行为及相间交互作用之机制。研究方法将包括理论建模、数值模拟和实验工作相结合。将使用多流体方法结合三相的总体平衡和LES-Euler/拉格朗日方法同时进行数值计算。这两种方法都必须扩展到允许考虑所有相关的传输机制的三相鼓泡塔模拟。这包括首先考虑所有重要的力，正确地描述气泡和粒子运动。本文将建立鼓泡塔反应器中颗粒与气泡相互作用、气泡诱导湍流和颗粒调制液体湍流的细观模型。因此，拟议的项目包括以下核心任务，每一个都结合了两种方法的详细验证和交叉比较：（1）模拟颗粒-气泡相互作用，包括可能的粘附力的粘附概率。该模型将以随机碰撞模型为基础，其中包括流体动力学相互作用。将引入两个相的附加阻力项，以描述被气泡拖曳的颗粒，反之亦然。这些模型的发展将得到格子玻尔兹曼模拟的支持，其中气泡被解决，粒子被视为点质量。(2)开发一种新的气泡聚结和破碎内核，考虑到气泡诱导湍流的影响，调制液相湍流的固体颗粒，和修改后的湍流对气泡聚结和破碎的影响。该模型将通过采用两个气泡群人口平衡模型来实现。(3)建立一个考虑气泡和固体颗粒对液相湍流调制的尺度效应和浓度效应的液相亚网格模型，并将其与两个气泡群粒子数平衡模型耦合，进行三相大涡模拟。此外，还将开发用于LES-Euler/拉格朗日模拟框架的亚网格湍流闭合。(4)采用PIV和ECVT技术对气-液-固三相鼓泡床反应器的流体力学参数和相分布特征，特别是液相湍流功率谱进行了实验研究。实验数据将用于验证三相鼓泡塔反应器的大涡模拟，以及双流体和欧拉/拉格朗日方法，并研究气液固三相的基本相互作用。本项目旨在揭示三相鼓泡床反应器中颗粒和气泡引起的湍流细观结构以及湍流调制的耦合机制。