【作者】 郑桂波；

【导师】 金宁德；

【作者基本信息】 天津大学 ， 检测技术与自动化装置， 2009， 博士

【摘要】 两相流动现象广泛存在于工业生产过程中,两相流流动参数检测对生产过程及工艺优化具有重要意义。由于两相流存在随机可变的相界面,使其流动结构复杂、流型多变,流动过程参数难于测量,同时两相流流动现象又表现为非平稳及多尺度非线性自组织模式特点。采用先进阵列传感器与现代信息处理技术融合的检测理论与方法,是解决复杂两相流流动参数检测的有效途径。针对石油工业中油井内特定测量环境的两相流参数检测问题,本文设计了能够同时测量两相流相含率及流量的插入式阵列电导传感器测量系统,在多相流实验装置测取动态测量信号的基础上,采用多尺度非线性分析方法研究了两相流流型非线性动力学特性,采用特征挖掘及信息融合的软测量方法实现了两相流流量参数测量。取得的创新性研究成果如下:1.采用有限元方法分析了插入式阵列电导传感器电场分布特性,对插入式阵列电导传感器几何尺寸进行了优化。在此基础上设计了可实现过压过流保护的电源模块、恒压恒流激励模式可选的激励信号发生模块、信号调理模块,并开发了基于嵌入式实时操作系统的便携式采集系统,可实现多路信号的高速并行采集,内嵌文件系统,可将采集数据通过USB扩展口直接存入可移动存储设备中;并通过串口、键盘与液晶实现人机交互。2.采用多尺度非线性两相流流型动力学特性分析方法。在此基础上分析了插入式阵列电导传感器在垂直上升气液两相流中采集的132种流动条件下电导波动信号。研究结果表明:利用小尺度熵变化速率特征可以分辨三种典型流型(泡状流、段塞流、混状流),而在大尺度熵值变化细节上可以反映各种流型的动力学特性。泡状流随机可变特性表现为大尺度熵的高值及振荡性;段塞流气塞与液塞的间歇性运动表现为大尺度熵的低值及平稳性;混状流极不稳定的振荡运动特性表现为介于泡状流及段塞流之间的熵值特点,并在更大尺度时熵值逐渐接近泡状流熵值。两相流多尺度熵分析有助于进一步理解流型转化动力学特性,多尺度熵值变化速率特征则是流型辨识的新指示器。3.针对插入式阵列电导传感器两相流流量软测量问题,本文采用基于粒子群算法和量子粒子群算法的支持向量机软测量模型,经对六种单峰或多峰测试函数搜索检验,证明了量子粒子群算法具有更高的支持向量机核函数关键参数搜索效率和寻优精度。在此基础上,从插入式阵列电导传感器相含率电极测取的相含率波动信号提取了时频域特征量,建立了基于量子粒子群算法的支持向量机软测量方法的相含率及分相流量预测模型,预测结果表明在水相流量范围为0.2方/小时～12方/小时,气相流量范围为7方/小时～60方/小时及含水率为0~0.6范围内,含水率预测的平均相对误差为2.06%,分相流量预测的平均相对误差为10%,取得了较高的测量精度。4.针对产气井气液两相流流量测量问题,提出了基于伞集流涡轮流量计与阵列电导传感器组合测量新方法。采用电导传感器瞬态波动信号的混沌吸引子形态特征的矩参数组合及低尺度与高尺度熵率特征量组合可以很好地辨识集流通道内不可视气液两相流流型特征。在伞集流条件下,采用涡轮流量计可实现较高精度的气液两相流总流量测量;在提取集流通道内电导波动信号时频域特征量前提下,结合涡轮流量计获取的流量测量信息,采用信息融合的软测量方法可实现较高精度的气液两相流分相流量测量,为油气田中低产量的气井内气液两相流流量测量探索了新的途径。更多还原

【Abstract】 Two phase flow phenomenon widely exists in industrial producing process and the measurement of the flow parameters is of great significance for industrial producing process and the optimization of process. The existence of randomly changing interface of two phase flow makes the flow structure complex and the flow pattern changeable, in which the parameters are difficult to measure. Simultaneously, the two phase flow phenomenon behaves as non-stable and multiscale nonlinear auto organization characteristic. Therefore it’s an effective approach to solve the measurement of complex two phase flow parameters by the fusion of advanced array sensors and modern information processing method and theory. In the paper which mainly aims at the two phase flow measurement problem in oil well of petroleum industry, a intrusive array conductance sensor is designed which is capable of measuring the phase fraction and flowrate simultaneously. Based on the dynamic signal measured by multiphase flow facility, the nonlinear dynamic characteristics of two phase flow patterns were studied by using multiscale nonlinear analyzing method. The flowrate of two phase flow was measured by soft measurement method based on characteristics extracting and information fusion. And the innovative research fruits are shown as below:1. The electrical field distribution characteristics of intrusive array conductance probe were analyzed using finite element method, and the geometry size of intrusive array conductance probe were optimized. Then the power module which could realize over voltage protection and over current protection, exciting module which could be set to constant voltage or constant current exciting mode and the signal modulation module were designed. And then a portable data acquisition system based on embedded real time operating system was developed, which could complete high speed parallel acquisition, had embedded file system and could save the sampled data in removable storage devices through USB peripheral communication port, which also could realize communication between machine and human by serial port, keyboard and LCD screen.2. The multiscale nonlinear dynamic characteristics analysis method of two phase flow patterns was brought forward. And then based on this, the fluctuant conductance signals of 132 two phase flow conditions were analyzed, which collected by using array conductance sensors in upward vertical gas-liquid two phase flow. The results indicated the changing rate of sample entropy at small scales could classify the three typical flow patterns (bubble flow, slug flow and churn flow), and the fluctuation of sample entropy of large scales reflected the dynamic characteristics of each flow pattern. The stochastic characteristic of bubble flow was shown as higher and oscillating sample entropy at large scales; the intermittence of gas slug and liquid slug of slug flow was represented as lower and stable sample entropy of large scales; the unstable and oscillating characteristics of churn flow behaved as the entropy between that of bubble flow and slug flow, and the entropy closed to that of bubble at larger scales. The multiscale entropy analysis of two phase flow is helpful for understanding the dynamic characteristics of flow pattern transition, and the rate of multiscale entropy is a new indicator of flow pattern identification.3. Aiming at soft measurement problem of two phase flowrate researched with intrusive array conductance probe, the support vector machine soft measurement model based on particle swarm algorithm and quantum particle swarm algorithm were developed. After the proof-testing with six single peak or multi peak functions, the algorithm was proved to have higher searching efficiency and higher accuracy of seeking optimum. Based on this, the temporal and frequency characteristics of the phase fraction fluctuant signal acquired by phase fraction electrode of intrusive array conductance probe were extracted, and then prediction model of phase fraction and phase flowrate based on support vector machine with the quantum particle swarm algorithm was established. The prediction results indicate that the average percent deviation of water flowrate fraction is 2.06% and that of individual phase flowrate is about 10% at the water phase flowrate range of 0.2m3/h～12 m3/h, the air flowrate range of 7m3/h～60 m3/h and the water flowrate fraction range of 0 ~ 0.6.4. For the flowrate measurement issue of gas-liquid two phase flow in gas production well, the combined measurement method of petal type concentration turbine flowmeter and array conductance sensor was proposed. The combination of moment parameter based on attractor morphological characteristics and the combination of rate of entropy of low-scale and high-scale calculated by transient fluctuating signals acquired by conductance sensor could effectively identify the unseen gas-liquid two phase flow patterns in concentration channel. The turbine flowmeter could measure the total flowrate of gas-liquid two phase flow with high-precision for the flow condition with petal type concentrating diverter. After the temporal and frequency characteristics of the phase fraction fluctuant signal of concentration channel were extracted, combined with the flowrate information gotten by turbine flowmeter, the high precision phase flowmeter of gas liquid two phase flow was predicted by soft measurement method based on information fusion, and the measurement method was indicated as a new way to solve the gas liquid two phase flow of median and low yield gas production well.更多还原