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1.
本文针对油田生产测井中应用很广泛的流体电容含水率计在理论上和实验上进行了详细的研究。根据现有的实验事实,提出了高含水测量模。该模型认为,对于油水泡状流,即使在水矿化度很高时,流体电容仪仍在0-100%的含水率范围内有油水分辨能力。  相似文献   

2.
油气润滑气液两相环状流流动特性分析   总被引:1,自引:0,他引:1  
建立油气润滑气液两相环状流的数学模型,通过Fluent仿真,研究水平管内环状流的形成机制以及油气流速对其影响趋势。结果表明:气液两相流型随气相速度的变化,从分层流向环状流和雾状流转变,其中分层流向环状流的转变是附壁效应和气相涡旋流动的结果,环状流向雾状流的转变是气相撕裂油相形成细小油滴,并均匀混合的结果;在一定范围内最短进口长度和气速成正比关系。  相似文献   

3.
采用高速摄像,得到内径为1.931 mm、1.042 mm、0.531 mm的竖直上升圆管内液氮流动沸腾的主要流型为泡状流、弹状流、搅拌流和环状流;并且在1.042 mm、0.531 mm管内发现受限气泡流.并绘制流型图,分析表面张力,压力和管径对流型转变的影响.表面张力是影响流型转变的重要物性参数,相对于空气-水的流型图,对应的弹状流/搅拌流,搅拌流/环状流流型转变线向较低的气体表观速度方向移动;而泡状流/弹状流的转变线向较高的气体表观速度方向移动.压力越高,相应的流型转变曲线向较低的气体表观速度方向移动.管径对流型转变有重要影响,随着管径的减小,相应的流型转变线向较低的气体表观速度方向移动.试验结果与通用的流型转变理论模型作比较,发现理论模型的预测结果与试验结果相差较大.  相似文献   

4.
陈妍  张弦  李国胜 《机械传动》2021,45(12):22-27
以渐开线直齿圆柱齿轮为研究对象,考虑热效应和时变效应,建立油水两相流模型和齿轮的热弹流润滑模型,探究了润滑油中含水率对油水两相流体的黏度及齿面润滑特性的影响.研究结果表明,润滑油中混入冷却水后,当含水率不超过5%时,随着含水率的增加,油水两相流体的黏度不断增大;含水率为5%时,油水两相流体的黏度达到其峰值,之后随着含水率的增加,油水两相流体的黏度不断减小.适当增加含水率可改善齿面的润滑特性,但考虑油膜温升及对设备的腐蚀磨损,应将含水率控制在5%以内.  相似文献   

5.
以渐开线直齿圆柱齿轮为研究对象,考虑热效应和时变效应,建立油水两相流模型和齿轮的热弹流润滑模型,探究润滑油中含水率对油水两相流体的黏度及齿面润滑特性的影响。研究结果表明:润滑油中混入冷却水后,当含水率不超过5%时,随着含水率的增加,油水两相流体的黏度不断增大;含水率为5%时,油水两相流体的黏度达到其峰值,之后随着含水率的增加,油水两相流体的黏度不断减小。适当增加含水率可改善齿面的润滑特性,但考虑油膜温升及对设备的腐蚀磨损,应将含水率控制在5%以内。  相似文献   

6.
基于经验模态分解和BP神经网络的油气两相流流型辨识   总被引:1,自引:0,他引:1  
基于经验模态分解(empidcal mode decomposition,EMD)BP神经网络,提出了油气两相流流型辨识的新方法。应用EMD将差压信号分解成不同频率尺度上的单组分之和,并提取组分的归一化能量作为流型辨识特征量。BP神经网络以这些能量特征量为输入对油气两相流不同流型(包括泡状流、塞状流、层状流、弹状流和环状流)进行分类。实验结果表明,本文提出的流型辨识方法是有效的,其中泡状流、塞状流、层状流、弹状流和环状流的辨识精度分别为100%、89.4%,93.3%、96.3%和96.9%。  相似文献   

7.
依据Mandhane图中环状流转变阈值,利用MATLAB软件将选取的阈值与已有的无量纲准则数进行关联,拟合得到油气润滑工况下新的间歇流-环状流转变的无量纲准则式;借助Fluent软件仿真验证该准则式的合理性,并通过仿真得到油气润滑中分层流-环状流、间歇流-环状流的流型转变图。研究结果表明,两相流流型仿真图中气液相分布规律与文献中对流型的描述一致,压降分布规律也基本符合已有的结论;由于管径小的原因,新的流型图转变曲线位置较Mandhane图环状流部分偏下,但曲线走势基本相同,故该流型图可以作为研究油气润滑环状流流型转变的依据。  相似文献   

8.
电容层析成像(ECT)技术因其非侵入、无辐射、可视化、响应快、成本低等优势在两相流测量中获得了广泛应用,但在发动机油路中,因摩擦产生的能量释放使磨粒荷电,对ECT传感器电容值的测量产生扰动,严重影响成像质量。为提高荷电颗粒存在情况下电容层析成像的图像重建质量,提出电容层析成像(ECT)与静电层析成像(EST)双模信息融合成像方法。该方法通过测量荷电颗粒在传感器矩形电极上感应的电荷值,得到荷电磨粒的信息;通过ECT系统得到一组电容值,并利用加权融合的修正方法,对ECT中畸变的电容值进行修正;用修正后的电容值进行图像重建。仿真实验证明:该方法能够弥补单一ECT模态的成像质量不高的不足,减弱荷电颗粒对ECT电容值测量的干扰,明显提高了图像重建质量,降低了成像误差;采用双模态重建图像方法可正确识别环状流、泡状流、核心流等几种典型流型。  相似文献   

9.
针对水平管道油水两相流流速的无扰动测量问题,提出一种基于超声/电学双模态传感器的流速测量方法。测量系统由连续波超声多普勒传感器和基于电容与电导的电学传感器构成,分别用于获取两相流流速和分相含率。由于连续波多普勒的测量区域集中于管道中心,受流速剖面、含率分布影响,所测得流速并非流体的总表观流速。在假设含率分布满足高斯分布的前提下,建立相含率加权的多普勒能量谱模型,将含率分布的影响因素引入总表观流速的测量,并建立总表管流速和分相表观流速的计算模型。在试验基础上,分别确定水连续和油连续时总表观流速计算模型的参数。试验表明,通过模型计算出的表观流速与实际测量的流速能够较好吻合,总表观流速的相对误差小于6.32%,分相表观流速的方均根误差小于5.64%。  相似文献   

10.
水平放置的Coriolis流量计中油水两相流滑脱特性研究   总被引:1,自引:0,他引:1  
本文通过流型观察与用Coriolis质量流量计测量油水混合物真实密度相结合的的方法对水平放置的Coriolis质量流量计中油水两相流中的持水率及相间的滑脱特性进行了实验研究,结果发现在含水率0.1~0.9、流速1.2~4 2m/s范围内,滑脱特性与管线中油水两相流的流型有很大的关系,油水相间既有正的滑脱,也存在负的滑脱。随着混合流量的增大,Coriolis质量流量计内,油水正负滑脱的转变点向持水率变小的方向移动。  相似文献   

11.
A water-driven annular type ejector loop is designed and constructed for air absorption. Fabricated ejector unit is horizontally installed in the loop, and annular water jet at the throat entrained atmospheric air through the circular pipe placed at the center of the ejector. The tested range of water flow rate is 160 L/min to 320 L/min and volumetric flow rate of water and air and local pressure are quantitatively measured using LabVIEW signal express program. For the quantitative measurement of bubble velocity, cinematic PIV technique using a high speed camera is adapted. In post processing, each bubble is used as seeding particles and ensemble averaged bubble velocity field at vertical plane of the ejector system is finally acquired. In the range of experiment, the bubble size distribution at downstream of the ejector seems to be quite uniform so that the flow can be classified as a homogeneous bubbly flow. In case of low range of water flow rate, the transition from bubbly flow to stratified flow occurs at the atmospheric outlet condition. As a comparative study, a numerical simulation on the same ejector shape is performed to understand the more detail hydrodynamic characteristics in the annular type ejector system. Homogeneous bubbly flow regime is used as default two-phase flow regime, and void fraction at the vertical plane of the ejector system is qualitatively compared with that of experiment. In volume flow rate comparison, numerical prediction agrees well with that of experiment where the homogeneous bubbly flow is maintained.  相似文献   

12.
液固两相流广泛存在于能源动力、石油化工等工业过程,两相流压降作为重要的流动参数,有助于流动建模及流态分析。建立液固两相压降测量模型,提出了一种结合超声多普勒及超声透射衰减的液固两相超声压降测量方法。搭建液固两相流动实验平台,对两相压降规律进行研究。两相混合流速和固相体积分数升高时,液固两相压降均逐渐增加。在固相体积分数为0.28%~1.37%,两相混合流速为0.9~1.65 m/s时,根据液固两相压降测量模型及Churchill模型的超声法得到的两相压降与差压传感器测量的压降平均相对误差为4.93%和5.10%,验证了测量模型的准确性。针对非均匀分布的两相流态进行压降测量,进一步拓展了压降测量模型的应用范围。本研究工作为非侵入超声法测量液固两相压降提供了方法基础。  相似文献   

13.
The progress of process tomography provides a new method for two-phase flow measurement. The dual-plane electrical resistance tomography (ERT) is combined with the correlation measurement technique to carry out the two-phase flow measurement in which the continuous phase is conductive liquid. The method of the estimation of void fraction and the disperse phase velocity by extracting the eigenvalue of the dual-plane ERT boundary measured data is presented. This method is applied to the transient flow-rate measurement of the air–water two-phase flow in vertical pipe. The information of disperse phase void fraction and distribution variation with time change can be considered adequately, and the estimated value of disperse phase void fraction and velocity can be gained fairly accurately in this method, which provides the data for the calculation of the transient flow-rate. The experiment results indicate that this kind of measurement method is valid when the distance between the upstream and downstream measured cross section is short enough.  相似文献   

14.
A micro wire-mesh sensor (μWMS) based on an electrical conductivity measurement between electrodes installed on the walls has been developed for gas–liquid two-phase flow measurements in a narrow rectangular channel. This measuring method applies a principle of conventional wire-mesh tomography, which can measure the instantaneous void fraction distributions in the cross-section of the relatively large flow channel. In two-phase flow measurement using μWMS the void fraction distributions in the narrow channel were obtained by the measured conductivities between electrodes arranged on each wall. Therefore, the gas phase structures and the bubble behaviors can be investigated in the flow channel with narrow gap. In the present paper, a μWMS for the air–water flow between parallel flat plates with a gap of 3 mm was developed and simultaneous measurements with a high speed video camera were conducted to compare the measured results in bubbly flow.  相似文献   

15.
Parameter measurement of gas–liquid two-phase flows with a high gas volume fraction (GVF) has received great attention in the research field of multiphase flow. The cone meter, as a new proposed differential pressure (DP) meter, is increasingly being applied in flowrate measurement of gas–liquid two-phase flow. A dual-parameter measurement method of gas–liquid two-phase flow based on a dual-cone meter is proposed. The two-phase flow is investigated in a horizontal pipeline with high GVF and low pressure, and exists in the form of annular flow. By adding a second cone meter, both gas mass fraction (GMF) and mass flowrate are measured. The pressure drop performances of five different sized cones have been discussed to make a cooperating cone selection and efficiently position the dual-cone in the pipe. Dual-cone flowmeter experiments of 0.45 and 0.65 equivalent diameter ratio combination, and 0.65 and 0.85 equivalent diameter ratio combination are respectively carried out to analyze the linearity of two-phase flow multiplier with Lockhart–Martinelli parameter and obtain the dual-parameter measurement results. The relative experiment error of GMF, gas mass flowrate and total mass flowrate are respectively within ±7%, ±5% and ±10%. The relative error of the liquid phase is within ±10% when the liquid mass fraction is beyond 40%. The experimental results show that it is efficient to utilize this dual-cone method for high GVF and low pressure gas–liquid two-phase flow measurement.  相似文献   

16.
In this work, a high speed ultrasonic multitransducer pulse-echo system using a four transducer method was used for the dynamic characterization of gas-liquid two-phase separated flow regimes. The ultrasonic system consists of an ultrasonic pulse signal generator, multiplexer, 10 MHz (0.64 cm) ultrasonic transducers, and a data acquisition system. Four transducers are mounted on a horizontal 2.1 cm inner diameter circular pipe. The system uses a pulse-echo method sampled every 0.5 ms for a 1 s duration. A peak detection algorithm (the C-scan mode) is developed to extract the location of the gas-liquid interface after signal processing. Using the measured instantaneous location of the gas/liquid interface, two-phase flow interfacial parameters in separated flow regimes are determined such as liquid level and void fraction for stratified wavy and annular flow. The shape of the gas-liquid interface and, hence, the instantaneous and cross-sectional averaged void fraction is also determined. The results show that the high speed ultrasonic pulse-echo system provides accurate results for the determination of the liquid level within +/-1.5%, and the time averaged liquid level measurements performed in the present work agree within +/-10% with the theoretical models. The results also show that the time averaged void fraction measurements for a stratified smooth flow, stratified wavy flow, and annular flow qualitatively agree with the theoretical predictions.  相似文献   

17.
This paper proposes a novel flow pattern identification method using ultrasonic echo signals within the pipe wall. A two-dimensional acoustic pressure numerical model is established to investigate the ultrasonic pulse transmission behavior between the wall-gas and wall-liquid interface. Experiments were also carried out at a horizontal air-water two-phase flow loop to measure the ultrasonic echo pulse signals of stratified flow, slug flow, and annular flow. It is interesting to find that the attenuation of the ultrasonic pulse at the wall-liquid interface is faster than the attenuation at the wall-gas interface. An RBF neural network is constructed for online flow pattern identification. The normalized envelop area and the area ratios of the echo spectrum are selected as the input parameters. The results show that the stratified flow, slug flow, and annular flow can be identified with an accuracy of 94.0%.  相似文献   

18.
When the oil field has been exploited by long-term water-flooding, it will be in high water-content stage of production. However, it is a great challenge for high-water-content measurement due to oil droplets extremely dispersed in the water. In this paper, we developed a phase-isolation based method for high-water-content oil-water two-phase flow measurement. Phase-isolation was realized by axial-flow swirler to concentrate scattered and random oil droplets into the pipe center and change the inlet flow pattern into a particular annular flow before measuring. Owing to the axisymmetric velocity and phase distribution, the electromagnetic flow meter avoided the effect of random distribution of insulating phase, and then had a good measurement performance for total volume flow rate. Furthermore, we respectively studied using axial pressure drop, radial pressure drop and the ratio of the two pressure drops to measure water content. The results showed that the ratio of the two pressure drops not only improves the resolution of oil and water, but also effectively reduces the impact of error transfer. In the dual-parameter measurement experiment, the relative errors of total volume flow rate and water content were almost within ±5%.  相似文献   

19.
A method for air–water two-phase flow measurement is proposed using a Venturi meter combined with an Electrical Resistance Tomography (ERT) sensor. Firstly, the real-time flow pattern of the two-phase flow is identified using the ERT sensor. Secondly, the void fraction of the two-phase flow is calculated from the conductance values through a void fraction measurement model, developed using the LS-SVM regression method. Thirdly, the mass quality is determined from the void fraction through void fraction-quality correlation. And finally, the mass flowrate of the two-phase flow is calculated from the mass quality and the differential pressure across the Venturi meter. Experimental results demonstrate that the proposed method is effective for the measurement of the mass flowrate of air–water flow. The proposed method introduces the flow pattern information in the measurement process, which minimizes the influence of flow pattern on the conventional differential pressure based methods. In addition, the mass quality is calculated from the void fraction, so the difficulty to obtain the mass quality in conventional methods is also overcome. Meanwhile, the new method is capable for providing concurrent measurements of multiple parameters of the two-phase flow including void fraction, mass quality and mass flowrate as well as an indication of the flow pattern.  相似文献   

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