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flow pattern map and time-frequency spectrum characteristics of nitrogen-water two-phase flow in small vertical upward noncircular channels

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EXPERIMENTAL THERMAL AND FLUID SCIENCE 2014年 54卷 47-60页

作者： Li, Hong-Wei Zhou, Yun-Long Hou, Yan-Dong Sun, Bin Yang, Yue Northeast Dianli Univ Sch Energy & Power Engn Jilin 132012 Peoples R China

We experimentally investigate the vertical upward gas-liquid two-phase flow in a 2 x 0.81 mm small rectangular channel and an equilateral triangle channel with a 2 mm side length. The two channels have same hydraulic diameters (D-h = 1.15 mm). We first present an experimental flow pattern map with nitrogen and water superficial velocities ranging from 0.08 m/s to 11.82 m/s and 0.12 m/s to 1.52 m/s, respectively. We also compare the flow pattern transition criteria between the triangle and rectangular cross sections by using the same hydraulic radius. We employ the influence rule that small passage geometry limits the flow pattern transition criteria. Thereafter, we comparatively analyze the transition boundaries of experiment flow patterns with other results in literature and classical prediction models. Results show that the cross-sectional shapes and experimental conditions of the experimental pipeline significantly affect the changes in the flow regime. Given the differential pressure signal of the two-phase flow, we propose two effective quadric time-frequency representations, namely, the adaptive optimal kernel time-frequency representation (AOK TFR) and data reduction sub-frequency band wavelet (DA SFBW) to investigate the complex behavior of vertical upward gas-liquid flows. We extract the positive power spectral density of the singular value-frequency entropy, singular value-frequency entropy, damping ratio, and vibration mode to characterize the evolution of flow patterns. The results suggest that the AOK TFR method can reveal flow dynamic details, whereas the DA SFBW based method is a powerful tool for characterizing the dynamical characteristics of different vertical upward gas-liquid flow patterns. (C) 2014 Elsevier Inc. All rights reserved.

关键词： Small channel two-phase flow flow pattern map Time-frequency representation

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A new flow pattern map for flow boiling in microfin tubes

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INTERNATIONAL JOURNAL OF MULTIPHASE flow 2015年 72卷 181-187页

作者： Rollmann, P. Spindler, K. Univ Stuttgart Inst Thermodynam & Thermal Engn ITW D-70550 Stuttgart Germany

The flow patterns during flow boiling of R134a in a horizontal microfin tube have been measured optically in a contiguous glass tube. The microfin tube is made of copper with a total fin number of 60 and a helix angle of 18 degrees. The fin height is 0.25 mm and the inner tube diameter at fin root is 8.72 mm. The copper tube is 0.5 m long. It is heated electrically. The glass tube is made of borosilicate glass. The inner tube diameter is 8.8 mm. The experiments have been conducted at the saturation temperature 10 degrees C and the heat flux 10,000W/m(2), The mass flux has been varied between 15 and 300kg/s m(2) in steps of 5 and 10 kg/s m(2), respectively. The vapor quality in the glass tube has been varied between 0.1 and 0.9 in steps of 0.1. The optical measurements based on the different intensity of reflected laser light at the phase interfaces. No reflections have been detected at the glass-liquid interface while there have been reflections at the glass-vapor interface. The laser source has been rotated by 360 degrees around the glass tube. Every 2.25 degrees measurements of the intensity have been made. Because of the different wetting behavior flow pattern maps for smooth tubes are not suitable for determining the flow patterns in microfin tubes. Due to the helical structure of the fins there is a new flow pattern, the helix flow, where the liquid phase flows helically through the microfin tube. Because of the large wetted surface this leads to an increase of the heat transfer coefficient. The transition curves for a new flow pattern map for microfin tubes are being derived. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： flow boiling flow pattern map flow pattern measurement R134a Microfin tube

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Thermo-hydraulic predictions for multi-pass evaporators by orthogonal collocation using a new flow pattern map

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APPLIED THERMAL ENGINEERING 2009年第2-3期29卷 601-606页

作者： Thyageswaran, Sridhar Coimbatore Inst Technol Dept Engn Mech Coimbatore 641041 Tamil Nadu India

A recently published paper by this author [S. Thyageswaran, Analysis of multi-pass evaporators using orthogonal collocation, Int. J. Refrigeration doi:10.1016/***.2007.06.011 (in press)], shows that orthogonal collocation is an effective alternative to traditional integration for the thermal analysis of multi-pass evaporators. The steady rate of heat exchanged (Q) and overall pressure drop (Delta p), for an R-22 based chiller having one shell and eight tube passes, were predi cted using the Kattan-Thome-Favrat and the Muller-Steinhagen and Heck models for the boiling R-22. While Q was over-predicted by 0.95%, Delta p was over-predicted by 20.3%. In the present work. results have been obtained using state-of-the-art, unified heat transfer and pressure drop sub-models based upon an improved flow pattern map by Wojtan et al. [L Wojtan, T. Ursenbacher, J.R. Thome, Investigation of flow boiling in horizontal tubes, part 1: a new diabatic two-phase flow pattern map, Int. J. Heat Mass Transfer 48 (2005) 2955-2969;L. Wojtan, T. Ursenbacher, J.R. Thome, Investigation of flow boiling in horizontal tubes, part 2: development of a new heat transfer model for stratified-wavy, dryout and mist flow regimes, Int. J. Heat Mass Transfer 48 (2005) 2970-2985], and Moreno Quiben and Thome [J.M. Quiben, J.R. Thome, flow pattern based two-phase frictional pressure drop model for horizontal tubes, part 1: diabatic and adiabatic experimental study, Int. J. Heat Fluid flow 28 (5) (2007) 1049-1059: J.M. Quiben, J.R. Thome, flow pattern based two-phase frictional pressure drop model for horizontal tubes, part 2: new phenomenological model, Int. J. Heat and Fluid flow 28 (5) (2007) 1060-1072]. The new predictions for Q and Delta p are 141.76 kW and 13.3 kPa, respectively, compared to their rated values of 140.67 kW and 13.789 kPa. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： flow boiling flow pattern map Frictional pressure drop Collocation Correlations

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New prediction methods for CO₂ evaporation inside tubes:: Part I -: A two-phase flow pattern map and a flow pattern based phenomenological model for two-phase flow frictional pressure drops

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2008年第1-2期51卷 111-124页

作者： Cheng, Lixin Ribatski, Gherhardt Quiben, Jesus Moreno Thome, John R. Ecole Polytech Fed Lausanne Lab Heat & Mass Transfer LTCM Fac Engn STI Stn 9 CH-1015 Lausanne Switzerland Univ Sao Paulo Dept Mech Engn EESC BR-13566590 Sao Carlos Brazil

An updated flow pattern map was developed for CO2 on the basis of the previous Cheng-Ribatski-Wojtan-Thome CO2 flow pattern map [1,2] to extend the flow pattern map to a wider range of conditions. A new annular flow to dryout transition (A-D) and a new dryout to mist flow transition (D-M) were proposed here. In addition, a bubbly flow region which generally occurs at high mass velocities and low vapor qualities was added to the updated flow pattern map. The updated flow pattern map is applicable to a much wider range of conditions: tube diameters from 0.6 to 10 mm, mass velocities from 50 to 1500 kg/m(2) s, heat fluxes from 1.8 to 46 kW/m(2) and saturation temperatures from -28 to +25 degrees C (reduced pressures from 0.21 to 0.87). The updated flow pattern map was compared to independent experimental data of flow patterns for CO2 in the literature and it predicts the flow patterns well. Then, a database of CO2 two-phase flow pressure drop results from the literature was set up and the database was compared to the leading empirical pressure drop models: the correlations by Chisholm [3], Friedel [4], Gronnerud [5] and Muller-Steinhagen and Heck [6], a modified Chisholm correlation by Yoon et al. [7] and the flow pattern based model of Moreno Quiben and Thome [8-10]. None of these models was able to predict the CO2 pressure drop data well. Therefore, a new flow pattern based phenomenological model of two-phase flow frictional pressure drop for CO2 was developed by modifying the model of Moreno Quiben and Thome using the updated flow pattern map in this study and it predicts the CO2 pressure drop database quite well overall. (C) 2007 Elsevier Ltd. All rights reserved.

关键词： model flow pattern map flow patterns phenomenological flow boiling two-phase flow frictional pressure drop macro-channel micro-channel CO2

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Integrated application of flow pattern map for long-term gas lift optimization: a case study of Well T in Indonesia

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JOURNAL OF PETROLEUM EXPLORATION AND PRODUCTION TECHNOLOGY 2020年第4期10卷 1635-1641页

作者： Rahmawati, Silvya Dewi Chandra, Steven Aziz, Prasandi Abdul Daton, Wijoyo Niti Gaol, Ardhi H. Lumban Inst Teknol Bandung Petr Engn Program Jalan Ganesha 10 Bandung Indonesia

Gas lift optimization has been a classic problem since its inception. The problem with currently practiced optimization, the gas lift performance curve (GLPC), was the sole requirement for exhaustive calculation that has to be performed every time changes to the reservoir are acknowledged. The approach of mechanistic modeling has been proven to be a powerful tool to complement the analysis of GLP curves, especially in complex, multi-well gas lift system. This publication offers a new approach in modeling the progression of flow pattern map (FPM) in case of reservoir pressure decline. The findings presented in this publication encourage the hypothesis that FPM can be used with minimum alteration should there be any changes in reservoir pressure.

关键词： Gas lift Performance curve Mechanistic modeling flow pattern map Optimization Correction factor

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A two-phase flow pattern map for annular channels under a DC applied voltage and the application to electrohydrodynamic convective boiling analysis

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2005年第25-26期48卷 5563-5579页

作者： Cotton, J Robinson, AJ Shoukri, M Chang, JS Dana Corp Therm Prod Long Mfg Div Oakville ON L6K 3E4 Canada McMaster Univ Dept Mech Engn Hamilton ON L8S 4L8 Canada Univ Dublin Trinity Coll Dept Mech & Mfg Engn Dublin 2 Ireland McMaster Univ Dept Engn Phys Hamilton ON L8S 4L8 Canada

An experimental study of tube side boiling heat transfer of HFC-134a has been conducted in a single-pass, countercurrent flow heat exchanger under an electric field. By applying 0-8 kV to a concentric inner electrode, the mechanics of EHD induced flow and heat transfer augmentation/suppression have been investigated for flow conditions with inlet qualities of 0% to 60%, mass fluxes from 100 kg/m(2) s to 500 kg/m(2) s, and heat flux levels between 10 kW/m(2) and 20 kW/m(2). A theoretical Steiner type two-phase flow pattern map for flow boiling in the annular channel under applied DC high voltage is also developed. The flow regimes encountered in the convective boiling process have been reconstructed experimentally and compared with the proposed EHD flow regime map. The results show that when the proposed dimensionless criterion M-d similar to Re-2 is satisfied, EHD interfacial forces have a strong influence on the flow pattern which is considered to be the primary mechanism affecting the increase in pressure drop and the augmentation or even suppression of heat transfer. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： two-phase flow electrohydrodynamics (EHD) convective boiling heat transfer flow pattern map

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Adiabatic vertical downward air-water flow pattern map: Influence of inlet device, flow development length and hysteresis effects

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INTERNATIONAL JOURNAL OF MULTIPHASE flow 2013年 56卷 126-137页

作者： Milan, Marco Borhani, Navid Thome, John Richard Swiss Fed Inst Technol EPFL Heat & Mass Transfer Lab LTCM CH-1015 Lausanne Switzerland

flow patterns for adiabatic vertical downward air water flow in an 8.8 mm diameter channel have been studied. In particular, the influence of the inlet device, the flow history and the development length on the flow pattern have been investigated and assessed. Test results with two inlet devices (highly mixed and unmixed) indicate that the inlet device has a major influence on the flow pattern transitions. Furthermore, the transition boundaries between different flow regimes have been found to depend strongly on the flow's development length, and display hysteresis effects. Not surprisingly, no existing flow pattern map worked well versus the current observations, nor did they agree with one another, thus pointing the need to better characterize the test section inlet geometry, the influence of the test length and the test procedure to obtain genuine flow pattern observations. Presently, it can be concluded that in each flow pattern region there are important differences in the actual flow structures. A future mechanistic flow pattern map should then not only contain flow pattern transition lines but also physical characteristics which describe the flow regime and inlet device effects. This was qualitatively done in this study by superimposing on the flow pattern maps frames which illustrate the characteristics of the flow for two different inlet devices. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： flow pattern map Two-phase flow flow visualization Inlet device Development length Hysteresis effects

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Development of boiling flow pattern map and heat transfer correlation of R32-oil mixture inside a horizontal micro-fin tube

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INTERNATIONAL JOURNAL OF REFRIGERATION 2023年 155卷 320-332页

作者： Li, Guang Zhuang, Dawei Xie, Liyi Ding, Guoliang Yue, Bao Fan, Bo Zhang, Hao Shao, Yanpo Shanghai Jiao Tong Univ Sch Mech Engn Inst Refrigerat & Cryogen Shanghai 200240 Peoples R China Tsinghua Univ Dept Engn Mech Beijing 100084 Peoples R China GD Midea Heating & Ventilating Equipment Co Ltd Foshan 528311 Peoples R China GD Midea Air Conditioning Equipment Co Ltd Foshan 528300 Peoples R China

R32 has been widely applied in room air-conditioners (ACs) because of its low GWP, and its heat transfer characteristics in refrigeration cycles may be affected by the lubricating oil mixed in R32. To quantitatively evaluate the effect of oil on the flow boiling heat transfer characteristics of R32, the flow pattern map and heat transfer correlation of R32-oil mixture are needed. In this study, an experimental rig for R32-oil mixture is established, in which the boiling flow patterns are observed and the heat transfer coefficients are measured. The experimental conditions cover the evaporation temperature ranging from -5 to 15 C-degrees, mass flux ranging from 100 to 400 kg m(- 2) s(- 1), vapor quality ranging from 0.1 to 0.9 and oil concentration ranging from 0% to 5%. A total of 80 flow patterns and 336 heat transfer coefficients have been obtained under the above experimental conditions. The results show that the flow patterns of R32-oil mixture contain stratified wavy flow, intermittent flow, annular flow and dryout flow, and the presence of the oil could promote the transformation from stratified wavy flow to annular flow;the heat transfer would be enhanced by the oil under lower vapor qualities and be deteriorated under higher vapor qualities. The boiling flow pattern map is developed based on observation results, which could well predict the flow patterns under the experimental conditions. The heat transfer correlation is developed based on the flow patterns and could predict 82% of the experimental results within a deviation of +/- 20%.

关键词： flow boiling R32-oil mixture Micro-fin tube Heat transfer flow pattern map Correlation Correlation

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A comparative analysis of a CO₂ evaporator model using experimental heat transfer correlations and a flow pattern map

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2014年 71卷 361-375页

作者： Patino, J. Llopis, R. Sanchez, D. Sanz-Kock, C. Cabello, R. Torrella, E. Jaume I Univ Dept Mech Engn & Construct E-12071 Castellon de La Plana Spain Univ Politecn Valencia Dept Appl Thermodynam E-46022 Valencia Spain

This work analyses and compares two approaches to evaluate the boiling heat transfer of CO2 in a real evaporation process: classical empirical correlations and flow pattern maps. We develop a finite-volume mathematical model of an evaporator to contrast both approaches and simulate it with four empirical correlations, not developed for CO2 but tested successfully with it, and a flow pattern map specific for CO2. We contrast the results of the simulation with 73 experimental steady-states performed with a transcritical CO2 refrigeration plant that incorporates a concentric counter current evaporator. We observe that both approaches can predict the evaporation process of CO2, nonetheless, in spite of the more complex mathematical formulation, the considered flow pattern map allows to obtain more precision. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： R744 flow pattern map Empirical correlation Evaporator model Uncertainty

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Two-phase flow pattern map for R170 in a horizontal smooth tube

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2016年 102卷 1141-1149页

作者： Zhuang, Xiaoru Gong, Maoqiong Chen, Gaofei Zou, Xin Shen, Jun Chinese Acad Sci Tech Inst Phys & Chem State Key Lab Technol Space Cryogen Propellants Beijing 100190 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

An experimental investigation of two-phase flow patterns and their transitions for R170 in a horizontal smooth tube was presented. The tests were conducted at various saturation pressures from 1.5 MPa to 2.5 MPa for different mass fluxes from 100 kg m(-2) s(-1) to 250 kg m(-2) s(-1) over the entire vapor quality range. The effects of mass flux and saturation pressure on two-phase flow pattern transitions were investigated and analyzed. The physical properties of velocity, viscosity and surface tension are important to the flow pattern transition criteria under our experimental conditions. Several two-phase flow pattern maps in horizontal tubes were compared with the experimental data. Finally, a new flow pattern map for R170 in a horizontal tube based on the Kim et al. (2012) map was carried out. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： flow pattern flow pattern map R170 Horizontal tube Two-phase

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