The method for study of vertical gas-liquid flow with foaming agent

The issue of operation water-cut and "self-kills" wells is one of major aspects in gas production. One of the methods of solving this problem is the introduction of foaming agent into the well. The effectiveness of these technologies requires a theoretical and experimental study of gas-liquid flow with surfactants. We have analyzed existing works and have found out that experimental research in this area was carried out at atmospheric pressure. At the same time, the pressure in the well varies with the length of the wellbore and can affect the properties of foaming agent. The article presents a description of a facility for the study of gas-liquid flows with foaming agents at different pressure values. A method of conducting experiments on the facility, simulating a section of the production tubing of a vertical gas well, has been developed. The relations allowing calculating the volume contents of the phases in the gas-liquid flow with surfactants are proposed.

Flow regimes and pressure drop of a composite tridimensional rotational flow sieve tray under concurrent gas--liquid flow

A new type of composite tridimensional rotational flow sieve tray is proposed. The flow pattern and operation domain of the tray were defined and divided by the image shooting method, combined with the standard deviation of the pressure difference sequence. There are membrane–drip column and foam–embolic flow in the TRST area of the internal packing–type tray, while bubbly and milk froth-ribbon flow are present in the packing area of the external packing-type tray. This study focused on the influence of the tray structure parameters on the pressure drop. Under the experimental operating conditions, the dry pressure drop was within 160 Pa, while the wet pressure drop was within 900 Pa. Under the same structural parameters, the internal packing–type pressure drop of the tray was higher than that of the external packing-type tray. A mathematical model of the pressure drop between dry and wet trays was established.

Study of interface gas-liquid flow characteristics in a rectangular microchannel for wavy-annular flow

The aim of this work is an experimental study of a gas-liquid flow in a rectangular slit microchannel with a cross-section of 200 × 2045 μm. Ethanol/water (95/5) mixture and nitrogen are used as working liquid and gas, accordingly. The external T-mixer is used for obtaining of wavy-annular flow pattern. The experimental data on interfacial waves and their characteristics in the meniscus area on the short side of the microchannel are obtained using high-speed visualization for a wide range of gas and liquid superficial velocities. Images are processed using the Python libraries to define the average liquid layer thickness and maximum amplitude of waves. An increase of gas superficial velocity causes decreasing in the average liquid layer thickness and maximal amplitude of the liquid layer thickness. The waves on the liquid layer surface (maximal amplitude) can be three times larger than the average liquid layer thickness for presented liquid and gas velocities. With increasing gas superficial velocities more liquid displace from the meniscus area to the liquid film on the wide side of the microchannel.

Application of the laser-induced fluorescence to study local characteristics of a gas-liquid flow in rectangular microchannel

The Laser-Induced Fluorescence (LIF) method was used to characterize liquid phase distribution in rectangular slit microchannel with cross-section 200×1205 μm for horizontal gas-liquid flow. Ethanol and nitrogen were used as working liquid and gas accordingly. The feature of this study is an application of hydraulic focusing cross-junction mixer for obtaining elongated bubble and transition flows in the microchannel with a high aspect ratio. Using LIF measurements for elongated bubble and transition flows the liquid film distributions were obtained for different distances from the bubble top and average liquid film thickness was compared with the prediction according to Taylor’s law.

Measuring the Continuity of a Gas-Liquid Flow in a Pipeline

The principles of building a meter for the continuity of gas-liquid flows in pipelines have been proposed, based on the polarized electromagnetic wave characteristics. A two-component flow in a pipeline has been analyzed considering the cross-sectional area of the flow in the pipeline. The judgment about the flow continuity by the phase difference between the electromagnetic fields polarized parallel and perpendicular to the wave propagation direction has been justified. The naturally and artificially anisotropic flow continuity measuring study results are given. A polarization technique of electromagnetic wave birefringence in the isotropic medium has been considered, based on placing an isotropic medium in an electric field formed by two capacitor electrodes. The possibility of eliminating the parameter measuring errors induced by temperature impact on the electromagnetic wave refractive index in controlled media is shown based on two electrodes of a capacitor creating an electric field in the dielectric pipeline measuring section as an option for implementing flat reflectors of an open resonator. The study results can be used in the instrument-making industry in the development and implementation of smart contactless measuring instruments in the gas-liquid flow analysis and control.

Experimental Study of Gas-Liquid Pressurization Performance and Critical Gas Volume Fractions of a Multiphase Pump

Gas entrainment may cause pressurization deterioration and even failure of pumps under conditions of high inlet gas volume fraction (GVF). When the inlet GVF increases to a critical value, an obvious deterioration performance of pump occurs. Air-water pressurization performance and inlet critical GVFs of a centrifugal multiphase pump are investigated experimentally under different inlet pressures and gas-liquid flow rates. To determine the first and second critical GVFs, a new method is proposed by computing the local extreme points of the second derivative of performance curves. New prediction correlations for two critical GVFs are established with relative errors lower than ±10% and ±8%. Boundaries of three different flow patterns and the transition flow rates are determined and presented by critical GVFs on the flow pattern diagram. Moreover, boundaries of maximum pressurization are determined by performance curve clusters and a power function correlation of gas-liquid flow rates when reaching the maximum pressurization is established. With the increase of inlet pressure from 1MPa to 5MPa, two-phase pressurization performance is significantly increased; occurrences of pressurization deterioration are obviously delayed with the first and second critical GVFs increasing by maximums of 8.2% and 7.1%.