The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Feng Dong - One of the best experts on this subject based on the ideXlab platform.
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local characteristic of horizontal air water Two Phase Flow by wire mesh sensor
Transactions of the Institute of Measurement and Control, 2018Co-Authors: Weiling Liu, Chao Tan, Feng DongAbstract:Two-Phase Flow widely exists in many industries. Understanding local characteristics of Two-Phase Flow under different Flow conditions in piping systems is important to design and optimize the industrial process for higher productivity and lower cost. Air–water Two-Phase Flow experiments were conducted with a 16×16 conductivity wire-mesh sensor (WMS) in a horizontal pipe of a multiPhase Flow facility. The cross-sectional void fraction time series was analysed by the probability density function (PDF), which described the void fraction fluctuation at different Flow conditions. The changes and causes of PDFs during a Flow regime transition were analysed. The local structure and Flow behaviour were characterized by the local Flow spectrum energy analysis and the local void fraction distribution (horizontal, vertical and radial direction) analysis. Finally, three-dimensional transient Flow fluctuation energy evolution and characteristic scale distribution based on wavelet analysis of air–water Two-Phase Flow ...
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oil water Two Phase Flow velocity measurement with continuous wave ultrasound doppler
Chemical Engineering Science, 2015Co-Authors: Xiaoxiao Dong, Chao Tan, Ye Yuan, Feng DongAbstract:Abstract A Flow velocity measurement method based on continuous wave ultrasound Doppler (CWUD) and Flow profile modeling is presented. A theoretical model is proposed to relate the overall superficial velocity of oil–water Two-Phase Flow with the mean velocity measured in the sensing volume of CWUD, by introducing velocity profile correlation. A CWUD measuring system was built to emit an ultrasonic wave of 1 MHz and collect the frequency shift of the reflected waves. Dynamic experiments were carried out in a horizontal pipe of inner diameter of 50 mm with the CWUD system. Six Flow patterns of horizontal oil–water Two-Phase Flow were observed including both the water continuous Flow and the oil continuous Flow. According to the results, the average frequency shift in oil–water Two-Phase Flow varies with the Flow pattern. The Flow velocity correlations are separately established for the oil continuous dispersed Flow, water continuous dispersed Flow and stratified Flow, based on the analysis of Flow velocity profile correction. The average relative error of the overall superficial velocity is 3.63% with a maximum relative error of 12.22%.
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identification of gas liquid Two Phase Flow regime through ert based measurement and feature extraction
Flow Measurement and Instrumentation, 2007Co-Authors: Chao Tan, Feng DongAbstract:Abstract Gas/liquid Two-Phase Flow is of great importance in various industrial processes. As the most important characteristic of a Two-Phase Flow, the Flow regime not only characterizes the Flow condition in an explicit way, but also determines the measurement model in each measuring method. Based on the application of Electrical Resistance Tomography (ERT) to a gas/liquid Two-Phase Flow on a vertical pipe, features reflecting the characteristics of gas/liquid Two-Phase Flow are extracted directly from the measured data without reconstruction of the cross-sectional images. The statistical features are derived through time series statistical analysis. Meanwhile features in the wavelet-scale domain are derived through both one-dimensional and Two-dimensional wavelet transform. All extracted features are considered as the input of a Support Vector Machine (SVM) algorithm to recognize the Flow regime. The preliminary results show that the feature extraction methods of multi-feature fusion and high-dimensional wavelet transform are suitable for the identification of gas/liquid Two-Phase Flow regimes.
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application of electrical resistance tomography to identification Two Phase Flow regime
International Conference on Machine Learning and Cybernetics, 2003Co-Authors: Feng Dong, Zhixu JiangAbstract:The application of the TERT-IV system prototype by Tianjin University to identify Two-Phase Flow regimes has been introduced. For the several typical Flow regimes, the method of principal component analysis and artificial neural neTwork to identify the Two-Phase Flow regimes is presented, and that is proved to have higher recognition rate by experimental test. The research results show that the method is feasible using feature extraction and analysis data to identify Two-Phase Flow regimes under different Flow conditions, and prove that it is possible that on line monitor the transportation process of air/water Two-Phase Flow using electrical resistance tomography (ERT) system.
Ningde Jin - One of the best experts on this subject based on the ideXlab platform.
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Flow pattern identification and nonlinear dynamics of gas liquid Two Phase Flow in complex neTworks
Physical Review E, 2009Co-Authors: Zhongke Gao, Ningde JinAbstract:The identification of Flow pattern is a basic and important issue in multiPhase systems. Because of the complexity of Phase interaction in gas-liquid Two-Phase Flow, it is difficult to discern its Flow pattern objectively. In this paper, we make a systematic study on the vertical upward gas-liquid Two-Phase Flow using complex neTwork. Three unique neTwork construction methods are proposed to build three types of neTworks, i.e., Flow pattern complex neTwork (FPCN), fluid dynamic complex neTwork (FDCN), and fluid structure complex neTwork (FSCN). Through detecting the community structure of FPCN by the community-detection algorithm based on K -mean clustering, useful and interesting results are found which can be used for identifying five vertical upward gas-liquid Two-Phase Flow patterns. To investigate the dynamic characteristics of gas-liquid Two-Phase Flow, we construct 50 FDCNs under different Flow conditions, and find that the power-law exponent and the neTwork information entropy, which are sensitive to the Flow pattern transition, can both characterize the nonlinear dynamics of gas-liquid Two-Phase Flow. Furthermore, we construct FSCN and demonstrate how neTwork statistic can be used to reveal the fluid structure of gas-liquid Two-Phase Flow. In this paper, from a different perspective, we not only introduce complex neTwork theory to the study of gas-liquid Two-Phase Flow but also indicate that complex neTwork may be a powerful tool for exploring nonlinear time series in practice.
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symbolic sequence analysis method of gas liquid Two Phase Flow measurement fluctuation signals
International Journal of Information Acquisition, 2006Co-Authors: Ningde Jin, Lingyu MiaoAbstract:Symbolic sequence analysis method was applied to analyze Two-Phase Flow measurement fluctuating signals and some issues about key parameters which were effect on the symbolic statistical quantities were discussed. Based on the above study, eighty groups differential pressure fluctuating signals of gas/liquid Two-Phase Flow were gathered in vertical upward pipes and we extracted the time irreversibility and chi-square statistics. When the gas superficial velocity is less than 0.02 m/s, the random variable motion feature and the dynamic character of bubble Flow become gradually complex with the gas superficial velocity increasing. When gas superficial velocity exceeds 0.02 m/s, the dynamic character of Flow pattern evolution becomes gradually simple from bubble Flow to slug Flow and the dynamic character becomes more and more complex from slug Flow to churn Flow with increasing gas superficial velocity. This study shows that time irreversibility and chi-square statistics are sensitive feature quantities of characterizing gas/liquid Two-Phase Flow patterns and this can better help for understanding dynamic characteristics of gas/liquid Two-Phase Flow patterns by observing the Two statistical quantities changing with the Two-Phase Flow parameters.
Haiqing Li - One of the best experts on this subject based on the ideXlab platform.
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air water Two Phase Flow measurement using a venturi meter and an electrical resistance tomography sensor
Flow Measurement and Instrumentation, 2010Co-Authors: Zhenzhen Meng, Haifeng Ji, Baoliang Wang, Zhiyao Huang, Haiqing LiAbstract:Abstract 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.
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application of electrical capacitance tomography to the void fraction measurement of Two Phase Flow
IEEE Transactions on Instrumentation and Measurement, 2003Co-Authors: Zhiyao Huang, Baoliang Wang, Haiqing LiAbstract:Based on the electrical capacitance tomography technique, a new method for the void fraction measurement of Two-Phase Flow is proposed. A 12-electrode void fraction measurement system is established. A mathematical model of image reconstruction of electrical capacitance tomography is developed. To obtain the quantitative information of Two-Phase Flow, combining the Tikhonov regularization principle and the algebraic reconstruction technique algorithm, a new image reconstruction algorithm is presented. The experimental results show that the accuracy of void fraction measurement is satisfactory. The proposed method is suitable for the void fraction measurement of many kinds of Two-Phase Flow.
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application of electrical capacitance tomography to the void fraction measurement of Two Phase Flow
Instrumentation and Measurement Technology Conference, 2001Co-Authors: Zhiyao Huang, Baoliang Wang, Haiqing LiAbstract:Based on electrical capacitance tomography technique, a new method for the void fraction measurement of Two-Phase Flow is proposed. A void function measurement system is established, A mathematical model of image reconstruction of electrical capacitance tomography is developed. To obtain the quantitative information of Two-Phase Flow, a new image reconstruction algorithm is presented. The experimental results show that the accuracy of void fraction measurement is satisfactory. The proposed method is suitable for the void fraction measurement of many kinds of Two-Phase Flow.
Gherhardt Ribatski - One of the best experts on this subject based on the ideXlab platform.
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Two Phase Flow characteristics during convective boiling of halocarbon refrigerants inside horizontal small diameter tubes
Heat Transfer Engineering, 2013Co-Authors: Daniel Semperteguitapia, Jessika De Oliveira Alves, Gherhardt RibatskiAbstract:Two-Phase Flow observations were performed for R134a and R245fa in 1.1- and 2.32-mm ID horizontal tubes. The tests were run for mass velocities ranging from 100 to 600 kg/m2-s and saturation temperatures of 22, 31, and 41°C. Additionally, an objective method to characterize Two-Phase Flow patterns was developed. This method is based on simultaneous processing of signals from the following devices: a pair of diodes laser-sensors with a transparent tube between them within which the Two-Phase Flow occurs, a micro-piezoelectric pressure transducer to determine the variation in the local pressure, and a microthermocouple within the fluid. The method was developed based on the k-means clustering algorithm, which consists of the gradual agglomeration of data of similar average characteristics. Simultaneous images of Two-Phase Flow were obtained through a high-speed camera (10,000 frames/s) and used to identify the following Flow patterns: bubbly, elongated bubbles, churn, and annular Flows. The maps obtained by...
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Two Phase Flow patterns and pressure drop inside horizontal tubes containing twisted tape inserts
International Journal of Multiphase Flow, 2012Co-Authors: Fabio Toshio Kanizawa, Gherhardt RibatskiAbstract:Abstract This paper presents an experimental study on Two-Phase Flow patterns and pressure drop of R134a inside a 15.9 mm ID tube containing twisted-tape inserts. Experimental results were obtained in a horizontal test section for twisted-tape ratios of 3, 4, 9 and 14, mass velocities ranging from 75 to 250 kg/m2 s and saturation temperatures of 5 and 15 °C. An unprecedented discussion on Two-Phase Flow patterns inside tubes containing twisted-tape inserts is presented and the Flow pattern effects on the frictional pressure drop are carefully discussed. Additionally, a new method to predict the frictional pressure drop during Two-Phase Flow inside tubes containing twisted-tape inserts is proposed.
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Two Phase Flow and heat transfer across horizontal tube bundles a review
Heat Transfer Engineering, 2007Co-Authors: Gherhardt Ribatski, John R ThomeAbstract:This paper presents a state-of-the-art review of Two-Phase Flow and Flow boiling across horizontal tube bundles. The review covers studies related to the dynamic aspects of Two-Phase Flow on the shell side of staggered and in-line tube bundles for upward, downward, and side-to-side Flows (i.e. the evaluation of void fraction, Two-Phase Flow behaviors and pressure drops). Heat transfer experimental work and heat transfer prediction methods on tube bundles in cross-Flow for plain, low-fin, and enhanced boiling tubes are also covered. The proposed Flow pattern maps and semi-empirical correlations for predicting void fraction and frictional pressure drop are critically described. These prediction methods are generally based on experimental results for adiabatic air-water Flows, and noticeable discrepancies are revealed in the results provided by them. This study reveals that before now, there were no heat transfer prediction methods that can be recommended as a general design tool. Finally, this study suggests further research focusing on the development of representative databanks and prediction methods.
John R Thome - One of the best experts on this subject based on the ideXlab platform.
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Two Phase Flow operational maps for multi microchannel evaporators
International Journal of Heat and Fluid Flow, 2013Co-Authors: Sylwia Szczukiewicz, Navid Borhani, John R ThomeAbstract:The current paper presents new operational maps for several different multi-microchannel evaporators, with and without any inlet restrictions (micro-orifices), for the Two-Phase Flow of refrigerants R245fa, R236fa, and R1234ze(E). The test fluids Flowed in 67 parallel channels, each having a cross-sectional area of 100 × 100 μm^2. In order to emulate the power dissipated by active components in a 3D CMOS CPU chip, Two aluminium microheaters were sputtered onto the back-side of the test section providing a 0.5 cm^2 each. Without any inlet restrictions in the micro-evaporator, significant parallel channel Flow instabilities, vapor back Flow, and Flow maldistribution led to high-amplitude and high-frequency temperature and pressure oscillations. Such undesired phenomena were then prevented by placing restrictions at the inlet of each channel. High-speed Flow visualization distinguished eight different operating regimes of the Two-Phase Flow depending on the tested operating conditions. Therefore, the preferred operating regimes can be easily traced. In particular, flashing Two-Phase Flow without back Flow appeared to be the best operating regime without any Flow and temperature instabilities.
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macro to microchannel transition in Two Phase Flow part 1 Two Phase Flow patterns and film thickness measurements
Experimental Thermal and Fluid Science, 2011Co-Authors: Chin Lee Ong, John R ThomeAbstract:The classification of macroscale, mesoscale and microscale channels with respect to Two-Phase processes is still an open question. The main objective of this study focuses on investigating the macro-to-microscale transition during Flow boiling in small scale channels of three different sizes with three different refrigerants over a range of saturation conditions to investigate the effects of channel confinement on Two-Phase Flow patterns and liquid film stratification in a single circular horizontal channel (Part 2 covers the Flow boiling heat transfer and critical heat flux). This paper presents the experimental Two-Phase Flow pattern transition data together with a top/bottom liquid film thickness comparison for refrigerants R134a, R236fa and R245fa during Flow boiling in small channels of 1.03, 2.20 and 3.04 mm diameter. Based on this work, an improved Flow pattern map has been proposed by determining the Flow patterns transitions existing under different conditions including the transition to macroscale slug/plug Flow at a confinement number of Co approximate to 0.3-0.4. From the top/bottom liquid film thickness comparison results, it was observed that the gravity forces are fully suppressed and overcome by the surface tension and shear forces when the confinement number approaches 1, Co approximate to 1. Thus, as a new approximate rule, the lower threshold of macroscale Flow is Co = 0.3-0.4 while the upper threshold of symmetric microscale Flow is Co approximate to 1 with a transition (or mesoscale) region in-between. (C) 2010 Elsevier Inc. All rights reserved.
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Two Phase Flow and heat transfer across horizontal tube bundles a review
Heat Transfer Engineering, 2007Co-Authors: Gherhardt Ribatski, John R ThomeAbstract:This paper presents a state-of-the-art review of Two-Phase Flow and Flow boiling across horizontal tube bundles. The review covers studies related to the dynamic aspects of Two-Phase Flow on the shell side of staggered and in-line tube bundles for upward, downward, and side-to-side Flows (i.e. the evaluation of void fraction, Two-Phase Flow behaviors and pressure drops). Heat transfer experimental work and heat transfer prediction methods on tube bundles in cross-Flow for plain, low-fin, and enhanced boiling tubes are also covered. The proposed Flow pattern maps and semi-empirical correlations for predicting void fraction and frictional pressure drop are critically described. These prediction methods are generally based on experimental results for adiabatic air-water Flows, and noticeable discrepancies are revealed in the results provided by them. This study reveals that before now, there were no heat transfer prediction methods that can be recommended as a general design tool. Finally, this study suggests further research focusing on the development of representative databanks and prediction methods.
