湿天然气管道低含液率气液两相流液滴夹带机理研究

发布时间：2018-01-11 01:26

本文关键词：湿天然气管道低含液率气液两相流液滴夹带机理研究　出处：《西安石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：在气液两相流动中,夹带率是一个非常重要的参数,对于管线、井筒和分离器设计等方面都有着很大的影响。当管道内气相速度足够高时,由于高气相速度的剪切作用,使得管道内气液界面易发生液滴夹带现象。被夹带液滴的速度一般接近于管线中气体的流动速度,这个速度远远高于低含量液体部分在管道底层的速度。液滴被夹带进入气相之后也改变了气相的密度,即使被夹带液滴的量是微小的,它对于管线压降和持液率的影响仍然很大,所以对于低含液量气液两相流工况液滴夹带机理的研究是非常重要的。通过对夹带率计算模型的改进,可以更加完善持液率和压降的预测模型,应用于实际工程中能够进一步提高管道运输效率。本文研究了湿天然气管道内低含液量气液两相流液滴夹带的形成机理,对现有的夹带率计算模型进行了综合分析。基于VB6.0平台将各模型的计算过程编制了模型求解程序,计算得到夹带率的值,并采用收集到的实验数据对各个模型作了验证和对比分析,给出了不同气液表观速度下的夹带率计算模型推荐使用情况,同时确定了一种最适用于低含液量气液两相流工况的夹带率计算模型—Zhang[27](2003)等人对Oliemans(1986)等的修正模型。之后对该模型进行了改进,用平均混合密度替换了气相密度参数,构建了一个计算夹带率的改进关系式。此外,基于实验数据对各夹带率计算模型进行了评价,通过将各模型的计算值与实验数据进行对比分析发现本文改进模型的计算精度更高,误差更小。最后,分析了气、液相粘度,管径和界面张力等参数对夹带率的影响。
[Abstract]:In gas-liquid two-phase flow, entrainment rate is a very important parameter, which has great influence on the design of pipeline, wellbore and separator. Due to the shear effect of high gas velocity, the phenomenon of droplet entrainment is easy to occur in the gas-liquid interface of the pipeline, and the velocity of the entrained droplet is generally close to that of the gas flowing in the pipeline. This velocity is much higher than the velocity of the lower liquid part at the bottom of the pipe. The droplet is entrained into the gas phase and changes the density of the gas phase, even if the amount of the droplet is small. It still has a great influence on the pressure drop and liquid holdup of pipeline, so it is very important to study the mechanism of droplet entrainment under the condition of gas-liquid two-phase flow with low liquid content. The prediction model of liquid holdup and pressure drop can be improved. In this paper, the formation mechanism of droplet entrainment of gas-liquid two-phase flow with low liquid content in wet natural gas pipeline is studied. The existing calculation model of entrainment rate is comprehensively analyzed. Based on the VB6.0 platform, the calculation process of each model is programmed to solve the model, and the value of the rate of entrainment is calculated. The experimental data collected are used to verify and compare the models, and the recommended usage of the models for calculating the entrainment rate under different apparent gas-liquid velocities is given. At the same time, a calculation model of entrainment rate for gas-liquid two-phase flow with low liquid content is established. [The modified model of Oliemans et al. 1986.After this model is improved, the gas phase density parameter is replaced by the average mixing density. An improved formula for calculating the entrainment rate is constructed. In addition, each model is evaluated based on the experimental data. By comparing the calculated values of each model with the experimental data, it is found that the improved model has higher accuracy and smaller error. Finally, the viscosity of gas and liquid phase is analyzed. The influence of pipe diameter and interfacial tension on the entrainment rate.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE832

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