气液混输管路压降模型研究

发布时间：2018-04-24 20:30

本文选题：气液混输管路 + 气液两相流流型　；参考：《长江大学》2017年硕士论文

【摘要】：随着石油工业的发展,以及不断上涨的石油需求,石油进口量的比例正在不断增大。这一现象使得人们越发的看重运输成本,使得在经济性和安全性上都具有一定优势的长输油气管道得到广泛的应用。长输管道的流型一般多为气液两相流,目前针对于气液两相流的研究多为水平两相流或者是铅直两相流,而气液混输管路在实际敷设过程中,经常会穿跨越一些障碍,这使得管道存在一定的倾角。由于气液两相流动的复杂性,导致直接套用水平两相流模型或铅直两相流模型时往往误差很大,其预测精度不高,现有的压降计算模型不具有广泛推广使用的能力,因此需要对气液两相流进行深入的研究。本文针对目前研究尚少的小角度大气液比两相流进行分析,围绕气液两相流的压降展开了以下几方面的研究:(1)对目前国内外气液两相流流型以及压降模型的研究进展进行了调研总结,调研发现在以往的研究中,倾斜管气液两相管流的流型研究相对较少,且大多数研究都采用经验流型法;对目前常用压降模型的局限性进行总结;对气液两相管流常用的三种处理方法以及压降的四种基本模型进行总结;(2)设计并开展小角度大气液比两相流研究实验。在内径为DN60、长8m的有机玻璃管内进行,测量两相流气体流速、液体流速、平均压力、管道压降、持液率和温度等基本参数,并利用高速摄像系统拍摄下实验中出现的流型,根据实验数据绘制出实验流型图,总结出管道倾角对流型的影响,对管道倾角为15°时的流型进行简单的流型划分;研究气液流速以及管道倾角对持液率和压降的影响,得出了流型以及流型的转变会对持液率和压降有直接影响的结论。因此,计算气液两相流压降时应优先采用基于流型的压降模型;(3)基于实验的基础上,对环状流的形成机理进行分析,并建立环状流形成的机理模型,给出流型转变界限方程。选择了两种持液率计算方法和基于流型的三种压降计算方法对实验条件下的理论持液率和压降进行预测。通过误差分析,选择误差最小的Beggs-Brill方法中的系数Ψ进行了角度修正,修正后误差明显降低。从而得出了修正后的小角度大气液比两相流压降计算公式。本文通过分析倾斜角度对压降造成的影响,对压降模型进行优选,然后选择合适的压降模型对其进行修正,从而得出适用于实验条件的经验计算公式,该公式能应用于小角度大气液比两相流压降的预测。
[Abstract]:With the development of oil industry and rising oil demand, the proportion of oil imports is increasing. This phenomenon makes people pay more attention to the transportation cost and makes the long oil and gas pipeline which has certain advantages in economy and security to be widely used. The flow pattern of long distance pipeline is usually gas-liquid two-phase flow. At present, most of the researches on gas-liquid two-phase flow are horizontal two-phase flow or vertical two-phase flow, and the gas-liquid mixing pipeline often crosses some obstacles in the course of practical laying. This results in a certain inclination of the pipe. Because of the complexity of gas-liquid two-phase flow, the error of the horizontal two-phase flow model or the vertical two-phase flow model is often very large, the prediction accuracy is not high, and the existing pressure drop calculation model does not have the ability to be widely used. Therefore, it is necessary to study the gas-liquid two-phase flow in depth. In this paper, the two-phase flow of small angle atmospheric liquid ratio, which has not been studied at present, is analyzed. This paper studies the pressure drop of gas-liquid two-phase flow in the following aspects: (1) the current research progress of gas-liquid two-phase flow pattern and pressure drop model at home and abroad is summarized. There are few researches on the flow pattern of gas-liquid two-phase pipe flow in inclined tube, and most of the researches are based on empirical flow pattern method, and the limitation of the commonly used pressure drop model is summarized. Three common treatment methods of gas-liquid two-phase pipe flow and four basic models of pressure drop are summarized and designed and the research experiment of small-angle gas-liquid ratio two-phase flow is carried out. In an 8 m long plexiglass tube with DN60 inner diameter, the basic parameters such as gas flow velocity, liquid velocity, average pressure, pressure drop, liquid holdup and temperature were measured, and the flow patterns in the experiment were photographed using a high speed camera system. According to the experimental data, the experimental flow pattern diagram is drawn, and the influence of the pipe inclination angle on the convection pattern is summarized, and the simple flow pattern is divided when the pipe inclination angle is 15 掳, and the effects of the gas-liquid velocity and the pipe inclination angle on the liquid holdup and pressure drop are studied. It is concluded that the flow pattern and its change have a direct effect on the liquid holdup and pressure drop. Therefore, in calculating the pressure drop of gas-liquid two-phase flow, the pressure drop model based on the flow pattern should be adopted first. Based on the experiments, the formation mechanism of the annular flow should be analyzed, and the mechanism model of the formation of the annular flow should be established, and the boundary equation of the flow pattern transition should be given. Two calculation methods of liquid holdup and three pressure drop calculation methods based on flow pattern are selected to predict the theoretical liquid holdup and pressure drop under experimental conditions. Through error analysis, the coefficient 蠄 of the Beggs-Brill method with the smallest error is selected for angle correction, and the error is obviously reduced after the correction. A modified formula for calculating the pressure drop of the two phase flow at a small angle is obtained. In this paper, by analyzing the influence of tilt angle on pressure drop, the pressure drop model is optimized, and then the appropriate pressure drop model is selected to modify it, and the empirical calculation formula applicable to the experimental conditions is obtained. The formula can be used to predict the pressure drop of the two phase flow at a small angle.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE832

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