EFFECT OF SURFACTANT ON TWO-PHASE FLOW PATTERNS OF WATER-GAS IN CAPILLARY TUBES

Flow patterns of liquid-gas two-phase flow were experimentally investigated. The experiments were carried out in both vertical and horizontal capillary tubes having inner diameters of 1.60 mm. The working liquid was the mixture of water and Sodium Dodecyl Benzoyl Sulfate (SDBS). The working gas was Nitrogen. For the water/SDBS mixture-gas flow in the vertical capillary tube, flow-pattern transitions occurred at lower flow velocities than those for the water-gas flow in the same tube. For the water/SDBS mixture-gas flow in the horizontal capillary tube, surface tension had little effect on the bubbly-intermittent transition and had only slight effect on the plug-slug and slug-annular transitions. However, surface tension had significant effect on the wavy stratified flow regime. The wavy stratified flow regime of water/SDBS mixture-gas flow expanded compared with that of water-gas.     

LUMPED PARAMETER NONLINEAR ANALYSIS OF PRESSURE DROP OSCILLATION IN TWO-PHASE FLOW IN EVAPORATOR TUBES

The pressure drop oscillation is analyzed by using a lumped parameter nonlinear model in this paper. It is concluded that the instability of pressure drop type can be deseribed by a second-order ordinary differential equation. The effect of operation condi- tions on the pressure drop oscillation can be examined by two dimentionless parameter and ri. The result obtained with the model agreed qualitatively with experimental results.     

CHARACTERISTICS OF PRESSURE DROP AND CORRELATION OF FRICTION FACTORS FOR SINGLE-PHASE FLOW IN ROLLING HORIZONTAL PIPE

Gas-liquid two-phase flow occurs increasingly in some dynamic devices operating in the oceanic condition. The relative data are limited with respect to flow characteristics, so the present study is to investigate systematically single-phase pressure drop, and to develop the theory for frictional factor under the rolling condition. Using deionized water as the test fluid, a series of experiments of single–phase flow were conducted in pipe with the inner diameter of 34.5 mm. The test section was horizontally settled on the rolling apparatus, and its regularity was similar to simple harmonic motion. It is found that the pressure drop during rolling motion fluctuate with the change of the rolling period and rolling angle, which is significantly different from fluid motion in a steady state. By the contrast between experiment results and stable-state theory values, existing correlations can not predict present frictional factor very well. Therefore, in the present article, the single-phase frictional factor is correlated with the Reynolds number for rolling motion, and its computated results agree well with experimental data.     

FLOW PATTERN AND PRESSURE LOSS OF OIL-WATER TWO-PHASE FLOW IN HORIZONTAL STEEL PIPE

Experimental Study on oil-water two-phase flow patterns and pressure loss was conducted on a horizontal steel pipe loop with 26. 1mm inner diameter and 30m total length. The working fluids are white oil, diesel oil and tap water. Several instruments, including a new type of liquidprobe are successfully integrated to identify 7 different flow patterns. The characteristics of the flow patterns and the transition process were observed and depicted in this paper.Investigation revealed that the pressure loss was mainly depended on the flow paiterns.     

SIMULATION OF LOW-CONCENTRATION SEDIMENT-LADEN FLOW BASED ON TWO-PHASE FLOW THEORY

Low concentration sediment-laden flow is usually involved in water conservancy, environmental protection, navigation and so on. In this article, a mathematical model for low-concentration sediment-laden flow was suggested based on the two-phase flow theory, and a solving scheme for the mathematical model in curvilinear grids was worked out. The observed data in the Zhang River in China was used for the verification of the model, and the calculated results of the water level, velocity and river bed deformation are in agreement with the observed ones.     

INFLUENCE OF INCLINATION ANGLE ON THE MOTION OF TAYLOR BUBBLES IN UPWARD SLUG FLOW

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＳｌｕｇｆｌｏｗｉｓｏｎｅｏｆｔｈｅｍｏｓｔｃｏｍｐｌｉｃａｔｅｄｆｌｏｗｐａｔｔｅｒｎｓａｎｄｏｃｃｕｒｓｏｖｅｒａｗｉｄｅｒａｎｇｅｏｆｇａｓａｎｄｌｉｑｕｉｄｆｌｏｗｒａｔｅｓｉｎｓｍａｌｌａｎｄｍｅｄｉｕｍｓｉｚｅｔｕｂｅｓ .Ｉｔｉｓｃｈａｒａｃｔｅｒｉｚｅｄｂｙｌａｒｇｅｂｕｌｌｅｔ ｓｈａｐｅｂｕｂｂｌｅｓ (ｒｅ ｆｅｒｒｅｄｔｏａｓｔｈｅＴａｙｌｏｒｂｕｂｂｌｅｓ) ,ａｌｍｏｓｔｆｉｌｌｉｎｇｔｈｅｔｕｂｅ ,ｗｈｉｃｈａｒｅｓｅｐａｒａｔｅｄｂｙｌｉｑｕｉ…     

INVESTIGATION ON FLOW AND HEAT TRANSFER CHARACTERISTICS OF ANNULAR TWO-PHASE FLOW THROUGH THE VENTURITUBE

A model that incorporates the important phenomena in the annular gas-water flow through the Venturi tube is presented. A series of experiments are carried out to measure the flow and heat transfer characteristics in cold and hot conditions. Comparison between numerical and experimental results shows good agreement.     

ANALYSIS OF TWO-PHASE FLOW PRESSURE BUILDUP DATA FROM WELL IN AN INFINITE MULTIWELL RESERVOIR

A general method has been developed for analyzing two-phase flow pressure buildup data from a well located in a system of both production and injection wells completed in an infinite muhiwell reservoir. The analysis technique assumes that the tested well has established its own drainage area before shut-in and a linear reservoir pressure trend dominates the well pressure behavior at the instant of shut-in. And for the two-phase flow problems the horizontal saturation gradients are assumed to be negligible. The entire pressure rcsponse, whether or not conventional semilog straight lines exist, can be analyzed and the Injection-Production Ratio （IPR）, the total fluid （oil/water） mobility, the average drainage-area pressure, and also the skin factor can be calculated much easily. The validity and applicability of the method are demonstrated by a field example. The technique by using the type curves for analyzing the pressure-buildup data is also presented here.     

NUMERICAL SIMULATION STUDY ON SURFACTANT FLOODING FOR LOW PERMEABILITY OILFIELD IN THE CONDITION OF THRESHOLD PRESSURE

Based on the non-Darcy flow characteristics of surfactant flooding in the low permeability oilfield, considering the changes of threshold pressure and influence of surfactant on convection, diffusion, adsorption and retention, a mathematical model is established for a three-dimensional, two-phase, three-component surfactant flooding. A new treatment for the changes of threshold pressure and a novel correction method for the relative permeability curve in the process of surfactant flooding are derived, which enhances the matching degree between the mathematical model and field practice. The mathematical model was used to perform the numerical simulation study for a pilot test of surfactant flooding in Chao 45 Block of Daqing Oilfield, a proper injection plan was optimized. After the optimized plan was carried out in oilfield, the desirable effects, like pressure-reducing, injection rate increase, and the increase of oil recovery, were achieved. The average oil increase for single well reaches 37%, the ratio of cost to revenue is above 1：4, so the economic effect of scale is promising.     

ANALYSIS OF TWO-PHASE FLOW PRESSURE BUILDUP DATA FROM A WELL IN AN INFINITE MULTIWELL RESERVOIR

NOMENCLATURE A1———drainage area of the tested well ( Well 1) At———total reservoir drainage area B———two-phase formation volume factor C———wellbore storage coefficient Cf———rock compressibility fator Co———oil compressibility fator Cw———water compressibility fator Ct———compressibility fator K———reservoir permeability m———slope of a semilog straight line m1———slope defined by Eq.(12) p-———average reservoir pressure-pD———di mensionless average drainag…     

BASIC EQUATIONS AND WAVE THEORY OF GAS-LIQUID TWO-PHASE TRANSIENT FLOW

This paper is aimed at a systematic discussion on the basic equations for two-phasetransient flow and the theory of pressure waves and interfacial waves.The characters of the ba-sic equations have been analyzed.The formulas for wave speed of pressure and interfacial waveshave been derived.It has been proved that various mathematical models can be unified by theproposed integrating model and various wave speed formulas can be unified by the derived uni-versal formula.The basic equations for the separated flow model are ill-conditioned because ofthe unreasonable neglect of the pressure differences between the phases and the interfaces.Driftflux model can improve the accuracy if some additional equations are provided.However theymust be carefully chosen.The basic equations for homogeneous flow model are well-conditionedand they can be used in two-phase transient flow,especially in the cases of no velocity slips be-tween the phases.     

IDENTIFICATION OF GAS-LIQUID FLOW REGIMES IN A HORIZONTAL FLOW USING NEURAL NETWORK

The knowledge of flow regimes is very important in the study of a two-phase flow system. A new flow regime identification method hased on a Probability Density Function (PDF) and a neural network is proposed in this paper. The instantaneous differential pressure signals of a horizontal flow were acquired with a differential pressure sensor.The characters of differential pressure signals for different flow regimes are analyzed with the PDF. Then, four charaeteristic parameters of the PDF curves are defined, the peak number (K1), the maximum peak value (K2), the peak position (K3) and the PDF variance (K4 ). The characteristic vectors which consist of the four characteristic parameters as the input vectors train the neural network to classify the flow regimes. Experimental results show that this novel method for identifying air water two-phase flow regimes has the advantages with a high accuracy and a fast response. The results clearly demonstrate that this new method could provide an accurate identification of flow regimes.     

SOLUTION OF RELATIVE PERMEABILITY OF TWO-PHASE FLOW IN POROUS MEDIUM

ＳＯＬＵＴＩＯＮＯＦＲＥＬＡＴＩＶＥＰＥＲＭＥＡＢＩＬＩＴＹＯＦＴＷＯ－ＰＨＡＳＥＦＬＯＷＩＮＰＯＲＯＵＳＭＥＤＩＵＭＬｕＹｕ－ｌｉｎ（ＩｎｓｔｉｔｕｏｆＥｎｇｉｎｅｅｒｉｎｇＭｅｃｈａｎｉｃｓ，ＤａｌｉａｎＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇ...     

THE LINEAR HOMOGENEOUS FLOW MODEL FOR TWO-PHASE FLOW INSTABILITY IN BOILING CHANNELS

ＮＯＭＥＮＣＬＡＴＵＲＥＤ　ｉｎｎｅｒｄｉａｍｅｔｅｒ (ｍ)Ｑ　ｈｅａｔｆｌｕｘ (ｋｗ/ｍ2 )ｆ　ｆｒｉｃｔｉｏｎａｌｒｅｓｉｓｔａｎｃｅｃｏｅｆｆｉｃｉｅｎｔＴ　ｔｅｍｐｅｒａｔｕｒｅ (°Ｃ)Ｇ　ｍａｓｓｆｌｏｗｖｅｌｏｃｉｔｙ (ｋｇ/ｓ.ｍ2 )ｔ　ｔｉｍｅ (     

PDA MEASUREMENTS OF TWO-PHASE FLOW STRUCTURE AND PARTICLE DISPERSION FOR A PARTICLE-LADEN JET IN CROSSFLOW

The two-phase flow structure and particle dispersion for a dilute particle-laden jet in crossflow(JICF) were experimentally investigated by means of Phase Doppler Anemometry(PDA) measurement.The two-phase flow experiments were conducted for different flow conditions and solid particle parameters,including the ratio of the jet velocity to crossflow velocity,the particle size and mass loading.The experimental results indicate that the fine particles with the size of 70 micron and the mass loading of 0.05% hav...     

TRANSIENT FLOWS AND PRESSURE WAVES IN PIPES

ＴＲＡＮＳＩＥＮＴＦＬＯＷＳＡＮＤＰＲＥＳＳＵＲＥＷＡＶＥＳＩＮＰＩＰＥＳＷａｎｇＸｉｕ－ｑｉｎｇ（ＮｕｃｌｅａｒＩｎｄｕｓｔｒｙＭａｎａｇｅｍｅｎｔＩｎｓｔｉｔｕｔｅ，ＰｏｓｔＯｆｆｉｃｅＢｏｘ１２６７，Ｂｅｉｊｉｎｇ１０２６００，Ｐ．Ｒ．Ｃｈｉｎ...     

NUMERICAL SIMULATION ON 2-D WATER-AIR TWO-PHASE FLOW OVER TOP OUTLET

Flood discharge over top outlet of dam is simu-lated by 2-dimension water-air two-phase mathematical model.Distribution of dynamic pressure, turbulent kinetic energy (k), turbulent dissipation rate (ε) , free water surface and veloci-ty field have been obtained. The simulated results were testedby physical model, which shows that the computed results areidentical with that of the physical model.     

A MODEL FOR PREDICTING PHASE INVERSION IN OIL-WATER TWO-PHASE PIPE FLOW

1. INTRODUCTION Flows consisting of mixtures of two immisciblefluids such as oil and water are encountered frequentlyin many areas of the process industry and in thepetrochemical industry. The phase inversion refers toa phenomenon where, with a small chan…     

ON THE MECHANISM OF DRAG REDUCTION IN HIGH CONCENTRATION NON-HOMOGENEOUS PIPE FLOW

In this paper a method for calculating the resistance force in high concentrationnon-homogeneous pipe flow is suggested.Comparing with experiment,it is shown that the theo-retical results are in good agreement with the experimental ones.     

STUDIES ON PROPERTIES OF FLOW CAVITATION NUMBER AND MINIMUM PRESSURE COEFFICIENT IN SHORT CLOSED CONDUITS

For a short closed conduit with smooth (streamline pattern) boundary, the comparison of minimum pressure coefficient at boundary, - Cpm , which obtained from model tests, with flow cavitation number a is possible to describe the property of preventing cavitation in the closed conduit.In this paper, analytical results show that the ratio σ/ - Cpm decreases with increasing Reynolds number Re, when the configuration of the conduit is designed, and this ratio approaches a constant when Re = 106 or so. The model test data for five engineering cases of the short closed conduit with various configuration indicates that the analytical results are reliable. Therefore, the value of the ratio σ/ - Cpm corresponding to that of Reynolds number in model (Re)m ≥106 must be taken so as to correctly describe the cavitation property of the studied conduit. The condition of Lr ≥ 10-4[(Re)p]2/3 should be satisfied ( Lr is model length scale; (Re)p is Reynolds number in prototype) when the model is designed by Froude cr