【作者】 薛国民；

【导师】 沈毅；

【作者基本信息】 哈尔滨工业大学 ， 控制科学与工程， 2008， 博士

【摘要】 多相流广泛存在于石油、化工、冶金等生产过程的各个领域,其参数检测对于资源的合理开发、生产安全及工业过程控制都具有非常重要的意义,目前已成为国内外给予极大关注的前沿课题。由于多相流流动的复杂性,其参数检测难度较大。本文根据油田多相流的特点,对多相流气液分离方法、流量测量和含水率测量方法等进行了深入研究。基于对气液重力分离和旋流分离原理的分析,得出重力分离方法存在分离速度慢、设备较大的问题,管柱旋流分离法存在要求入射速度高、压损大的问题。研究了多圈螺旋管气液分离方法,推导了螺旋管内气液分离力学方程,给出了气液分离的边界条件,并进行了数值模拟。提出了一种重力与螺旋管离心力复合优化的气液分离器结构,给出了分离器总体结构设计原则和具体结构参数设计计算方法,研制了实验分离器,设计了液位Fuzzy-PID控制系统,实验结果证明,此结构分离器的分离性能优良,气液分离总量是同尺寸重力分离器的2.5倍。考虑到分离后的气相含有少量液滴,标准孔板用于计量含液湿气时,范围度只有3:1,压力损失较大,液体在孔板前聚集,所以有必要改进标准孔板结构。本文提出了一种锥形管变面积环孔装置,用于湿气计量,采用锥形管、内圆形可移动阻流件、精密弹簧和位移传感器组合的结构设计,给出了用位移代替差压的气体流量方程。可变流通面积比设计为5:1时,测量范围度可扩大到15:1。流体力学数值模拟结果表明,此装置内流体的速度场、压力场均匀稳定,压力损失是标准孔板的三分之一,避免了液体聚集、取压管堵塞等问题。考虑到分离后的液相含有少量气泡,液相计量是三相流计量问题,国内外多传感器融合三相流测量方法取得了较好的应用,本文提出一种基于弯管流量计与电导传感器的油气水三相流的测量方法,推导了三相流流量、含水率、含气率测量的理论模型,实验结果表明:在流速范围0.4-4m/s,体积含气率5%,含水率50%-90%范围内,流速测量值相对偏差<0.5%,含水率测量值相对偏差<2.5%,含气率测量误差<2%。针对液相含气的情况,研究了电容、短波含水测量法的适用性,基于均相流模型和两种物质混合后介电常数计算的H-B公式,给出液相含有少量气泡时,电容、短波测量含水率的理论方程,从理论上分析了温度升高和矿化度升高对含水率测量结果的影响;针对介质温度变化的情况,给出γ射线法测量含水率的温度补偿算法;实验结果与理论分析结果是一致的。更多还原

【Abstract】 Multiphase flow exists in various kinds of fields, such as petroleum, chemistry and metallurgy. And its parameter measurement plays an important role in resource exploration, production safety and industrial process control. A great deal of attention has been paid to this field, which has become a leading subject both home and abroad. Since multiphase flow is a complex process, it is quite difficult to measure its parameters. According to characteristics of multi-phase flow, the gas/liquid separating methods, flow rate measuring methods and water ration measuring methods are deeply investigated.Based on principle analyzing of gravity and ratation separating measure methods, the problems of low separating officiency and big volume on gravity separator and big pressure lose for big entry rate on circle cylinder separator are confirmed. Multi-cycle spiral tube gas liquid separating method is studied. The dynamic formula is derived. And the boundary conditions of gas liquid separating are given. The numerical simulation is done.A compound optimazation separator structure combined gravity with spiral centrifugal power is developed. The entire design rules and structure parameters calculating methods are given. The test separator is developed.The fuzzy-PID control system of separator’s level is designed. The experiments show the performance of this separator is good. The separating efficiency is 2.5 times of that of same shape size gravity separator.Considering there are some liquid drops in gas phase. There are some problems for measuring wet gas flow with standard orifice plate, such as the rangeability being 3:1, big pressure loss and liquid aggregation near the upstream orifice plate. So, it is necessary to improve the structure of the standard orifice plate. A tapered tube variable area ring orifice device for wet gas measure is developed. It combines a tapered tube, an inner circle-shaped movable baffle, a precision spring and a displacement sensor. Flow equation is given, with distance displacement for pressure difference. The rangeability can be as large as 15:1 in the case that the area ratio of the variable flow path is designed to be 5:1. The hydromechanical numerical simulation results indicate that both speed field and pressure field inside the device are stable and the pressure loss is one-third of the standard orifice plate. Further, the problems of liquid aggregation and pressure ducts block are avoided..Considering there are still some bubbles in liquid phase,the measurement of liquid phase is still three phase measurement. The multi-sensor methods for three-phase measurement are well used. A method combined elbow tube and conductance sensor is developed. The measure models of flow rate, water ratio and gas ratio are given. Experiments show that the relative error of flow rate is less than 0.5%, the relative error of water ratio is less than 2.5%, the error of measuring gas ratio is less than 2%, on the conditions of flow rate range being 0.4-4m/s,gas volume ratio being 5%, water volume ratio being 50%-90%。Aiming at gas existing in liquid, capacitance and short wave methods for water content ratio measurement are studied. Based on uniformity model and H-B formula, the water content ratio measure formula of capacitance and short wave for oil gas water three phase flow is given. The influnces of temperature and mineralization is analysed. Aiming at temperature changing, the temperature equalized formula forγray water content meter is given. The experimental results accord with the theory conclusions.更多还原