基于V型内锥与电导环的油水两相流参数测量

油水两相流在石油工业过程中十分常见,对其流动过程参数(如流量与含率)的准确测量一直受其流态的复杂性限制而成为科学研究与工业应用中亟待解决的重要课题。差压法是常用的流量测量手段,作为差压式流量计的一种,V型内锥式流量计结合两相流动模型可实现两相流流量的测量。电学法通过测量两相混合物电学性质(如电导率与介电常数)的变化实现分相含率的测量。本文采用等效直径比0.65的V型内锥式流量计结合环形电导式传感器阵列实现50mm内径水平管道中油水两相流总流量、含率与分相流速的测量,针对油水两相流特性修正Chisholm分相流差压测量关系式实现油水两相流质量流量的测量,并利用环形电导式传感器阵列实现含水率与质量含油率的测量。实验结果表明,油水两相流含水率测量的平均相对误差为8.1%,质量含油率的平均相对误差为13.7%,基于修正关系式与含水率、质量含油率测量结果的油水质量流量测量平均相对误差为4.4%,油相与水相表观流速的平均相对误差分别为3.2%与15.7%。本工作为进一步提高油水两相流过程参数的测量精度打下基础。     

利用涡街流量计测量油水两相流流量

为了考察涡街流量计在油水两相流中的测量特性,在内径为50 mm的垂直上升管道内,对不同混合流量、含油率下的涡街信号进行了实验测量,并对油水两相仪表系数和斯特劳哈尔数予以分析.结果表明,在含油率5%～40%内,仪表系数相对误差小于4%,斯特劳哈尔数相对误差随含油率增加有变大趋势、随混合流量增加有减小趋势,而且在两相雷诺数2×104～5×104内可视为常数,并随雷诺数降低而升高.实验说明油水两相流中存在稳定的两相涡街,利用涡街流量计测量油水两相混合流量具有可行性.     

管径大小对水平圆管油水两相流的影响

不同情况下,油水两相在水平圆管中流动会形成不同的流型,研究流型的影响因素对合理选择管道参数、管道腐蚀与防护以及油水分离具有重要意义。应用Fluent软件对不同入口速度下及不同管径的水平圆管油水两相流流型进行数值模拟,分别得到不同入口速度模型下不同管径水平圆管内的油水两相体积分数云图,画出流型图,并分析。结果表明:入口速度0 m/s~0.5 m/s时,管径对流型变化无明显影响;入口速度1.0 m/s~2.0 m/s时,管径大小成为影响水平圆管油水两相流流型的关键因素。     

油田多相流计量方法研究与探讨

分析了多相流分离计量和在线计量方法,总结了多相流计量的核心技术和研究进展,分析了弯管流量计测量油水和气水两相流实验数据,结果表明弯管测量油水两相流准确性较好,测量气水两相流误差较大.探讨了弯管流量计与密度计或与其它流量计配合的测量方案.     

电导式相关流量计应用于油井井下流量测量

本文提出了一种新型的电导相关流量计,其敏感元件采用两个电导传感器,该流量能够应用于高含水油井的油水两相流流量测量,在多相流动实验装置上进行的实验表明,该流量计测量的流速范围宽,线性好,该流量计已经在大庆油田进行现场试验,使用该流量计在井下测量的油水的总流量与地面计量结果对比良好。     

科氏质量流量计灵敏度温度补偿方法研究

科氏质量流量传感器(Coriolis Mass Flowmeter,简称CMF)是高精度直接敏感流体质量流量的多参数测量仪表,精度高,重复性好。随着质量流量计的广泛应用,用户逐渐开始关注外界因素产生的测量误差,其中流体温度对测量精度的影响是用户关注的主要误差之一。本文从科氏质量流量计的敏感机理出发,建立流量计的灵敏度模型,并依据材料的弹性模量随温度变化的模型,建立了流量计的灵敏度和温度的补偿模型。改造现有的静态称重法质量流量计标定装置,对建模的流量计进行精度与流体温度的实验研究。理论与实验结果表明:科氏质量流量计随着流体温度的升高,将产生正向的测量误差,误差与温度的关系为二次曲线关系,在特定的温度范围内,可以简化为直线关系;利用论文研究的温度补偿模型,流量计从未补偿时的温度与精度关系+0.05347%/℃降低为补偿后的-0.00625%/℃,补偿效果显著。     

科里奥利质量流量计诞生30年暨高准扎根中国20年

4月23日，在上海浦东新区的艾默生过程管理高准（Micro Motion）公司内，举行了一个隆重而不失简朴的仪式，庆祝高准公司科里奥利（Coriolis）质量流量计（简称科氏流量计）诞生30周年和高准扎根中国20周年。高准公司总裁Tom Moser先生专程来华出席了庆典，并与艾默生过程管理流量部亚太区副总裁路伯舒（Trey Rothenberger）先生、     

科氏流量计应用于气液两相流测量的实验研究

以空气-水为介质,对科氏流量计应用于气液两相流双参数测量进行了实验研究.实验过程中保持液相流量一定,通过加入不同体积分数的空气来分析含气率对科氏流量计测量精度的影响,采用Weisman垂直上升管气液两相流流型图与实验数据进行了比较.结合实验结果,初步归纳出含气量、流型和科氏流量计测量精度之间的关系,总结出液相中含气影响科氏流量计测量精度的主要因素及其影响规律,为进一步研究科氏流量计气液两相流测量误差修正提供了一种技术方法.     

含两个相间裂纹叶片的失谐叶盘结构振动特性研究

基于集中质量叶盘结构模型,推导了含两个相间裂纹叶片的失谐叶盘结构的振动方程,揭示了两个相间裂纹叶片对叶盘结构振动特性的影响规律。比较分析了含两个相间裂纹叶片与含一个裂纹叶片的失谐叶盘结构振动特性的差异。分析结果表明,两个相间裂纹叶片引起了重固有频率对的显著分离,增大了振动局部化程度,导致叶盘结构的振动特性更加复杂。另外发现两个对裂纹深度变化极不敏感的特殊叶片,这可为工程中裂纹叶片的检测提供理论依据。     

密度对质量流量计测量原油含水率的影响

针对利用质量流量计测量原油含水率的过程中油水密度的问题，对其原理及影响测量精度的密度因素进行理论分析，并根据含水率监测误差发生的原因进行分析，总结质量流量计在原油含水监测中出现的误差的调整措施，为该型仪表在原油计量方面的应用做了进一步的探索。     

A flow rate measurement method for horizontal oil-gas-water three-phase flows based on Venturi meter,blind tee,and gamma-ray attenuation

Online horizontal oil-gas-water three-phase flow rate monitoring is essential for reliable operations during industrial production. A flow rate measurement method is developed in horizontal oil-gas-water three-phase flows by combining a blind tee, a Venturi meter, and a gamma-ray densitometer. The blind tee is installed at the test section entrance to homogenize the mixture by transforming the horizontal flow to a vertical upward flow. The Venturi meter is used for the total flow rate measurement. The dual-energy gamma-ray densitometer is used for phase holdup measurement. In the present method, blind-tee mixing effects and oil-water mixture slip behavior is essential, which were experimentally analyzed in this work. The phase inversion was found in the oil-water mixture with the increasing of the oil volume fraction. Besides, the addition of the gas reduces the oil-water slip ratio. For the range of 0–35% and 65–100% oil fraction in the oil-water liquid, the oil-water mixture can be well treated as a pseudo homogenous liquid with a slip ratio of 0.9–1.1. A three-phase flow rate model is then established for these conditions. The method was validated by horizontal oil-gas-water three-phase flows with average relative errors of 3.2% for the total flow rates, 4.3% for the gas flow rates, 11.5% for the oil flow rates, and 7.8% for the water flow rates.     

Measurement of velocity of sand-containing Oil–Water two-phase flow with super high water holdup in horizontal small pipe based on thermal tracers

When oil fields enter the last production period, the water holdup in the well is extremely high. Chemical flooding and horizontal well technology are often used to enhance oil recovery. These techniques result in a high downhole fluid viscosity and serious sand production, which leads to the failure of common velocity measurements because of sticking sand, and yields new logging difficulties. This paper presents a method of the velocity measurement of sand-containing oil–water two-phase flow in a super high water holdup pipe diameter based on thermal tracers. The measurement accuracy of the thermal tracer velocity method is related closely to parameters that affect its performance. Parameter optimization is required to improve the measurement accuracy. ANSYS Fluent was used for a numerical simulation of the heat-source shape and material, thermistor probe installation position and fluid heating power, and the method was verified experimentally. The optimal parameters of the thermal tracer flowmeter were obtained by numerical simulation, the heat source material was aluminum and the shape was rectangular. The thermistor probe was located 160–220 mm from the heat source, and the pulse heating power was 350 W. The experiment results show that the accuracy of the thermal tracer flowmeter was 4%, the repeatability was 2.6%, and the measurement accuracy of the flow velocity was unaffected by water holdup and sand.     

科里奥利质量流量计传感器零点模型研究及应用

科里奥利质量流量计以其直接测量质量流量的特点,成为近年来发展最为迅速的流量仪表之一,已经成为贸易结算的首选计量器具。虽然科里奥利质量流量计的测量精度很高,但是其存在零点漂移的缺陷,降低了仪表的长期稳定性。本文以典型的U型振动管传感器为例,基于振动管的幅频和相频特性,分析了传感器的各阶模态对于工作频率的响应,以此建立了传感器的初始相位模型。通过样机实验证明,该理论模型在应用于薄壁振动管时具有较高的计算精度和适用性,并将科里奥利质量流量计在低温介质测量中的测量误差降低到±0.3%以内,也为抑制科里奥利质量流量计零点漂移提供了理论依据。     

计及负频率影响的科里奥利质量流量计信号处理方法

采用滑动Goertzel算法计算科里奥利质量流量计信号的相位差时，存在较长的收敛过程，其主要原因之一是忽略了负频率成分的贡献。基于DTFT递推算法，提出了一种计及负频率影响的科里奥利质量流量计信号处理方法。首先采用自适应格型陷波滤波器对科里奥利质量流量计的传感器输出信号进行滤波并求得其频率，然后采用计及负频率影响的DTFT递推算法计算两路信号之间的实时相位差，再通过频率和相位差计算出时间差，从而求得质量流量。仿真结果表明，该方法可极大缩短相位差和时间差计算的收敛过程，具有较高的计算精度，且当应用于实际的系统时不易发生数值溢出。     

Accurate mass flow and density of bubbly liquids using speed of sound augmented Coriolis technology

Speed of sound augmented Coriolis technology utilizes a process fluid sound speed measurement to improve the accuracy of Coriolis meters operating on bubbly liquids. This paper presents a theoretical development and experimental validation of speed of sound augmented Coriolis meters. The approach utilizes a process fluid sound speed measurement, based on a beam-forming interpretation of a pair of acoustic pressure transducers installed on either side of a Coriolis meter, to quantify, and mitigate, errors in the mass flow, density, and volumetric flow reported by two modern, dual bent-tube Coriolis meters operating on bubbly mixtures of air and water with gas void fractions ranging from 0% to 5%. By improving accuracy of Coriolis meters operating on bubbly liquids, speed of sound augmented Coriolis meters offer the potential to improve the utility of Coriolis meters on many existing applications and expand the application space of Coriolis meters to address additional multiphase measurement challenges.The sources of measurement errors in Coriolis meters operating on bubbly liquids have been well-characterized in the literature. In general, conventional Coriolis meters interpret the mass flow and density of the process fluid using calibrations developed for single-phase process fluids which are essentially incompressible and homogeneous. While these calibrations typically provide sufficient accuracy for single-phase flow applications, their use on bubbly liquids often results in significant errors in both the reported mass flow, density and volumetric flow. Utilizing a process fluid sound speed measurement and an empirically-informed aeroelastic model of bubbly flows in Coriolis meters, the methodology developed herein compensates the output of conventional Coriolis meters for the effects of entrained gas to provide accurate mass flow, density, volumetric flow, and gas void fraction of bubbly liquids.Data presented are limited to air and water mixtures. However, by influencing the effective bubble size through mixture flow velocity, the bubbly liquids tested exhibit decoupling characteristics which spanned theoretical limits from nearly fully-coupled to nearly fully-decoupled flows. Thus, from a non-dimensional parameter perspective, the data presented is representative of a broad range of bubbly liquids likely to be encountered in practice.     

科里奥利颗粒料质量流量计流量公式理论分析

本文通过对科里奥利固体颗粒料质量流量计的结构分析，认为该流量计无法获取实时的质量流量，并对公开的瞬时流量计算公式进行了理论分析，说明其理论上的缺陷，给出了详细的推证过程和更为精确的理论计算方法和措施。     

A DSP-based signal processing method and system for CMF

A set of digital signal processing method is formed by combining a digital band-pass filter, an adaptive lattice notch filter and the DTFT algorithm considering negative frequency contribution for processing the signals of Coriolis mass flowmeter. A digital Coriolis mass flow transmitter is developed with a DSP chip to realize the signal processing approach. Some effective measures are proposed to ensure high accuracy and real time of this approach in the implementation. Simulations, electrical signal tests and water flowrate calibrations are conducted to validate the performances of the method and the system.     

数字信号处理技术在科氏质量流量计中的应用

科氏质量流量计是目前应用范围最广、发展速度最快的流量计之一。数字信号处理技术是科氏质量流量计的核心技术,直接决定其测量精度、测量稳定性等性能指标;而流量传感器输出信号的数学模型是信号处理的依据和基础。国内外学者提出了多种信号处理方法,但是,没有根据不同的信号模型和不同的应用场合对各种信号处理方法进行比较和评价。为此,根据不同数字信号处理方法的特征量提取原理,分析了其具有的优缺点。针对科氏质量流量计单相流、批料流与气液两相流测量这3种典型应用场合中存在的关键技术问题,依据随机游动信号模型、突变信号模型和自回归滑动平均(ARMA)信号模型,分别从计算精度、响应速度、收敛性、抗干扰能力和对参数变化的敏感度等方面,对不同信号处理方法进行考核和对比,确定了3种典型应用场合下,解决关键技术问题,性能最佳的数字信号处理方法。     

A study of mass flow rate measurement based on the vortex shedding principle

Mass flow rate measurement is very important in the majority of industry processes because the mass of fluid is not affected by ambient temperature and pressure as the volume will be. Conventional mass flow rate is normally derived from the volumetric flow rate multiplied by fluid density. The density can be obtained by a densitometer or calculated according to the temperature and pressure measured by a thermometer and pressure gauge respectively. However the measurement accuracy is not always satisfactory. Flowmeters directly measuring mass flow rate have been studied and developed recently, such as Coriolis and thermal flowmeters. Unfortunately they still have some limits in practical applications. A new method in which mass flow rate can be directly measured based on the vortex shedding principle is presented in this paper. As a vortex flowmeter, von Kàrmàn vortex shedding is generated by a bluff body (vortex shedder), leading to a pressure drop and pressure fluctuation. A single differential pressure sensor is employed to detect the pressure difference between upstream and downstream sides of the vortex shedder. Both vortex shedding frequency and pressure drop are contained from the output signal of the differential pressure sensor, so that the mass flow rate can be obtained from the pressure signal. Numerical simulation has been done to analyze the characteristics of the fluid field and design the measurement device. The Computational Fluid Dynamics (CFD) codes Fluent were used in the numerical simulation. Experiments were carried out with water and gas, and the results show that this method is feasible and effective to measure the mass flow rate. This method has also robustness to disturbances such as pipe vibration and fluid turbulence.