气液混合流体喷射器内两相混合机理及其多因素耦合机制

The liquid holdup of natural gas is one of the key factors affecting the natural gas production. The investigations of two phase flow mixing mechanism of mixed fluid ejector are of great significance to the development of effective natural gas ejector, which can be used to boost low pressure natural gas. The present project focuses on the mixed gas-water ejector, when the two phase flow pattern changes from mist flow to high liquid holdup flow. The mixing processes of two flow streams inside the ejector will be investigated through visualization experiment and numerical simulation. The study will be carried out under different liquid characteristic parameters(droplet diameter, droplet flow rate, liquid holdup), structural parameters and operating parameters, and the quantitative influences of these parameters on the ejector performance and two stream mixing processes will be revealed. The droplet flow characteristics will be studied for mist flow, and also the transformation of two phase flow pattern inside the ejector will be investigated for high liquid holdup flow. Then the evolvement rules of shock train and its multi-facor coupling mechanism will be obtained, and the quantitative method about non-dimensional parameters will be set up to characterize the shock train. On the basis of all the previous studies, an analytical energy efficiency model with multi-factor coupling will be developed for the ejector, and the general method about decreasing irreversible loss during mixing processes will be obtained. The project can enrich the theoretical system of gas-liquid two phase flow ejector, and it is of great significance to the effective production of natural gas in China.

天然气生产过程中的持液率是影响其生产的关键问题之一，研究混合流体喷射器内两相混合机理对开发天然气喷射器实现低压天然气高效开采具有重要意义。本项目对雾状流和高持液率的气液混合流体两相喷射器展开研究，通过数值模拟和可视化实验研究两相喷射器内两股流体的混合过程，获得液相特征参数（液滴直径和流量、持液率）、结构参数和运行参数对混合流体两相喷射器整体性能及两股流体混合过程特征参数的定量影响规律；查清雾状流两相喷射过程中液滴的运动规律及高持液率两相喷射过程中两相流流型的变化规律，进而揭示混合过程中激波链的演变规律及其多因素耦合机制，建立激波链无量纲特征参数的定量表征方法；综合相关研究结果，建立喷射器的多因素耦合能效分析模型，获得降低混合过程不可逆损失的普适性方法。本项目可丰富气液两相喷射的理论体系，为我国低压天然气高效开采提供理论和技术基础。

本项目以低压天含液然气高效开采为研究背景，对超音速气/汽液两相喷射混合机理及两相喷射器性能开展了系统研究，搭建了不同含液率（从低含液率雾状流、高含液率到纯水）的气液两相混合喷射实验平台，建立了超音速气液两相喷射器的数值计算模型，通过实验和数值模拟研究了两相混合流型的变化规律，分析了混合过程中激波链特征参数的变化规律，获得了液相特征参数（液滴直径、流量和含液率）、运行参数（高压压力、低压压力和背压）和结构参数等对两相混合过程及喷射器性能的定量影响规律；在综合考虑多因素耦合作用的基础上，开展了喷射器内流体混合过程的理论研究，建立了多因素耦合影响的喷射器性能计算模型，实现了对喷射器性能和内部流场结构的定量预测，揭示了超音速气液喷射器内两相混合机理及其多因素耦合机制；并据此提出了采用旁路、两级喷射、花瓣形喷嘴等提高喷射器性能的新方法。本项目研究结果进一步丰富了气液两相喷射的理论体系，为我国低压天然气高效开采提供理论和技术基础。基于上述研究结果，相关研究结果发表SCI论文17篇(含ESI论文1篇)，培养博士和硕士研究生7名。