Zhao Yulong, Zhang Yanbin, Jiang Youcai, Chen Donggen
Testing System of Servo Valve Flow Characteristics

Electro-hydraulic servo valve widely used in servo system is one key component translated electronic signal to hydraulic signal. The servo valve capability influences the character of servo system directly. Flow characteristic is one important performance index judging servo valve capability. To master their characteristic, must do many experiments. Virtual instrument technology is adopted in one testing system of Servo Valve Flow Characteristic; soft measure method can test steady-state flow and instantaneous dynamic flow; all test data can be on-line processing, storage and printed. According to testing result, the valve flow characteristic can be calculated automatically. Rationality and reliability of this testing system is verified by practical test and contrast experiment.

Zhang Jianjun, Sun Difei, Shi Huining. Yang Yongxiang, Li Xu, Wang Chi
Establishment of Expermental Calibrating Facilities for Oil-air-water Three-phase Flow

Technical specifications, Principle, work procedure, structural features, function, test procedure and analysis of uncertainty for oil-air-water three-phase experimental facility are introduced. According to the specifications, it is found that the establishment of the device is successful and some experience for further work are accumulated.

Shaomin Zhou, Jouko Halttunen
Application of Electrical Impedance Tomography in Pulp Flow Measurement

Electrical impedance tomography is an imaging method that can profile the resistivity distribution within a domain using a non-invasive sensor. It is a promising method for multiphase flow measurement. This paper describes an EIT system for monitoring the consistency, air bubbles and velocity in pulp flow.

Chen Deyun, Li Xiaolong. Quan Zhiying, Zhu Xiaofei, Sun Liquan
Concentration Measurement of Oil-Water Two-Phase Flow in Electrical Capacitance Tomography System

Concentration is one of the most important parameters in oil-water two-phase flow, and it is of great significance to get on an accurate measurement for concentration in the course of production and engineering control. Electrical Capacitance Tomography (ECT) technique, which can calculate the space distribution of dielectric constants in the inner of objects by measuring EC values between electrodes around the surface of objects, is being mainly applied to detect multiphase flows in industrial pipelines. And the technique also can offer visual information that conventional instruments can not detect in closed pipelines or containers, such as concentration, distribution, motion state of non-conducting multiphase. The subject investigated of this paper is major in the ECT system of 8-electrode oil-water two-phase flow, and the measuring principle is analyzed. At the same time, we present the method of image reconstruction to accomplish the concentration measurement of oil-water two--phase flow. In ART image-reconstruction algorithm, we present threshold value to improve quality of image reconstruction and calculating accuracy of content, and generally the measurement error is about 1%. Such method can well solve many defects that other measurement methods have, such as slow speed, high cost, and poor security and so on. Therefore, it offers a new method for the concentration measurement of oil-water two-phase flow.

S Al-lababidi, M L Sanderson
Transit Time Ultrasonic Modelling in Gas/Liquid Intermittent Flow using Slug Existence Conditions and Void Fraction Analysis

In this paper, the performance of the clamp-on transit time ultrasonic flowmeter is experimentally investigated in two-phase gas/liquid flow in straight pipes. Experiments on air-water horizontal slug flows in a 50 mm id pipe were conducted over operating conditions covering 0.3-4.0 m/s and 0.6-3.0 m/s gas and liquid superficial velocity ranges, respectively. The mathematical model presented in this paper is an improvement on the previous closure method which was developed by Al-Lababidi & Sanderson. The algorithm of the new mathematical model is based on both the analysis of the slug existence conditions and the statistical signals analysis of the conductivity probes measurements. Minimum and average liquid heights were evaluated using the PDF (Probability Density Function) analysis of conductance probe measurements. Using this approach, it is demonstrated that the ultrasonic clamp-on flowmeter provides good agreement with mathematical correlations for predicting the slug body velocity with ± 5 %.