The Study of Exhausting Accumulated Liquid in Upward Inclined Pipe Using a Swirl Tool

2019 ◽  
Author(s):  
Zhenqiang Xie ◽  
Xuewen Cao ◽  
Fachun Liang ◽  
Jun Zhang
Keyword(s):  
Flow Pattern ◽  
Cross Section ◽  
Centrifugal Force ◽  
Annular Flow ◽  
Gas Flow ◽  
Swirling Flow ◽  
Flow Patterns ◽  
Gas Production ◽  
Gas Velocity ◽  
The Cross

Abstract The problem of accumulated liquid is very common in wet gas gathering pipelines which varies with the topography, this phenomenon is much more serious especially in upward inclined pipelines. The existence of accumulated liquid at the bottom of the pipeline would decrease the area of the cross section that gas flows through. This makes the gas velocity fluctuate unpredictably and even results in shocks and blocks in pipelines which may cause danger in the safety management of oil and gas production. Swirl tool is a kind of rigid tool which can transfer different flow patterns to a flow pattern similar to annular flow and it has been successfully used to exhaust accumulated liquid in oil fields. However, the mechanism of swirling flow generation in a swirl tool is not fully understood and few researchers have explained how the annular-similar flow decays. In this paper, the formation mechanism of swirling flow in a swirl tool is analyzed using a physical method. The flow pattern transfer procedure and distribution of gas and liquid in the cross section of the pipeline in the swirl tool is simulated with FLUENT (a commercial CFD code). Following the swirling flow formation analysis, the decay of the annular-similar flow from the outlet of the swirl tool is also simulated with FLUENT (a commercial CFD code). Also, the effects of different superficial gas velocities and different liquid rates on the decay of the annular-similar flow are studied with the swirl tool fixed at the bottom of the upward inclined pipeline. The results show that the formation of swirling flow in a swirl tool is mostly affected by the geometric structure of the swirl tool. The centrifugal force is the main force which transfers different flow patterns to a flow pattern similar to annular flow. The centrifugal force that acts on liquid is larger than that of gas since the density of the liquid is much bigger than gas. The annular-similar flow starts to take shape in the swirl tool after the first thread pitch, but the annular-similar flow is nonuniform. After about three thread pitches, the annular-similar flow becomes uniform with liquid surrounding the inner wall of the pipe and gas flowing in the core region of the pipe. The distance of the annular-similar flow sustains longer when the superficial gas velocity increases which means the decay of the swirling flow is slower. Since sufficient liquid rate is critical to maintain annular-similar flow after the tool when the gas flow rate is fixed, the distance of the annular-similar flow goes longer if there is a little increase in liquid rate.

scholarly journals Flow Pattern Map of Flow Boiling in a Rectangular Channel Filled with Porous Media

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2440
Author(s):  
Youngwoo Kim ◽  
Dae Yeon Kim ◽  
Kyung Chun Kim
Keyword(s):  
Porous Media ◽  
Flow Pattern ◽  
Flow Regime ◽  
Annular Flow ◽  
Flow Boiling ◽  
Rectangular Channel ◽  
Flow Patterns ◽  
Flow Pattern Map ◽  
Mist Flow ◽  
Churn Flow

A flow visualization study was carried out for flow boiling in a rectangular channel filled with and without metallic random porous media. Four main flow patterns are observed as intermittent slug-churn flow, churn-annular flow, annular-mist flow, and mist flow regimes. These flow patterns are clearly classified based on the high-speed images of the channel flow. The results of the flow pattern map according to the mass flow rate were presented using saturation temperatures and the materials of porous media as variables. As the saturation temperatures increased, the annular-mist flow regime occupied a larger area than the lower saturation temperatures condition. Therefore, the churn flow regime is narrower, and the slug flow more quickly turns to annular flow with the increasing vapor quality. The pattern map is not significantly affected by the materials of porous media.

scholarly journals NMR Analysis Method of Gas Flow Pattern in the Process of Shale Gas Depletion Development

Geofluids ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-7
Author(s):  
Rui Shen ◽  
Zhiming Hu ◽  
Xianggang Duan ◽  
Wei Sun ◽  
Wei Xiong ◽  
...  
Keyword(s):  
Flow Pattern ◽  
Pore Pressure ◽  
Shale Gas ◽  
Gas Flow ◽  
Continuous Medium ◽  
Slip Flow ◽  
Flow Patterns ◽  
Transitional Flow ◽  
Analysis Method ◽  
Adsorbed Gas

Shale gas reservoirs have pores of various sizes, in which gas flows in different patterns. The coexistence of multiple gas flow patterns is common. In order to quantitatively characterize the flow pattern in the process of shale gas depletion development, a physical simulation experiment of shale gas depletion development was designed, and a high-pressure on-line NMR analysis method of gas flow pattern in this process was proposed. The signal amplitudes of methane in pores of various sizes at different pressure levels were calculated according to the conversion relationship between the NMR T 2 relaxation time and pore radius, and then, the flow patterns of methane in pores of various sizes under different pore pressure conditions were analyzed as per the flow pattern determination criteria. It is found that there are three flow patterns in the process of shale gas depletion development, i.e., continuous medium flow, slip flow, and transitional flow, which account for 73.5%, 25.8%, and 0.7% of total gas flow, respectively. When the pore pressure is high, the continuous medium flow is dominant. With the gas production in shale reservoir, the pore pressure decreases, the Knudsen number increases, and the pore size range of slip flow zone and transitional flow zone expands. When the reservoir pressure is higher than the critical desorption pressure, the adsorbed gas is not desorbed intensively, and the produced gas is mainly free gas. When the reservoir pressure is lower than the critical desorption pressure, the adsorbed gas is gradually desorbed, and the proportion of desorbed gas in the produced gas gradually increases.

Flow Boiling Visualization of R-134a in a Vertical Channel of Small Diameter

2007 ◽  
Author(s):  
Claudi Marti´n-Callizo ◽  
Bjo¨rn Palm ◽  
Wahib Owhaib ◽  
Rashid Ali
Keyword(s):  
Flow Pattern ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Bubbly Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
R 134A ◽  
Heated Length

The present work reports on flow boiling visualization of refrigerant R-134a in a vertical circular channel with internal diameter of 1.33 mm and 235 mm in heated length. Quartz tube with a homogeneous ITO-coating is used allowing heating and simultaneous visualization. Flow patterns have been observed along the heated length with the aid of a digital camera with close-up lenses. From the flow boiling visualization, seven distinct two-phase flow patterns have been observed: Isolated bubbly flow, confined bubbly flow, slug flow, churn flow, slug-annular flow, annular flow, and mist flow. Two-phase flow pattern observations are presented in the form of flow pattern maps. Finally, the experimental flow pattern map is compared to models developed for conventional sizes as well as to a microscale map for air-water mixtures available in the literature, showing a large discrepancy.

scholarly journals Investigations of mass transfer in annular gas-liquid flow in a microreactor

2016 ◽  
Vol 37 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Paweł Sobieszuk ◽  
Karolina Napieralska
Keyword(s):  
Mass Transfer ◽  
Cross Section ◽  
Chemical Reaction ◽  
Liquid Flow ◽  
Annular Flow ◽  
Gas Flow ◽  
Absorption Rate ◽  
Transfer Coefficients ◽  
Water Solutions ◽  
Gas Liquid Flow

Abstract The paper presents an investigation of mass transfer in gas-liquid annular flow in a microreactor. The microreactor had a meandered shape with a square cross-section of the channel (292×292 μm, hydraulic diameter 292 μm) and 250 mm in length. The rate of CO2 absorption from the CO2/N2 mixture in NaOH (0.1 M, 0.2 M, 0.7 M, 1.0 M and 1.5 M) water solutions was measured. Two velocities of gas flow and two velocities of liquid flow were used. In two cases a fully developed annular flow at the beginning of the channel was observed, whilst in two cases annular flow was formed only in about 2/3 of the microchannel length. Based on the measurements of CO2 absorption rate, the values of volumetric liquid - side mass transfer coefficients with the chemical reaction were determined. Then physical values of coefficients were found. Obtained results were discussed and their values were compared with the values predicted by literature correlations.

An Experimental Study on Air-Water Two-Phase Flow Patterns in Pebble Beds

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Bai Bofeng ◽  
Liu Maolong ◽  
Su Wang ◽  
Zhang Xiaojie
Keyword(s):  
Experimental Study ◽  
Flow Pattern ◽  
Test Section ◽  
Slug Flow ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Pattern Transition

An experimental study was conducted on the air-water two-phase flow patterns in the bed of rectangular cross sections containing spheres of regular distribution. Three kinds of glass spheres with different diameters (3 mm, 6 mm, and 8 mm) were used for the establishment of the test section. By means of visual observations of the two-phase flow through the test section, it was discovered that five different flow patterns occurred within the experimental parameter ranges, namely, bubbly flow, bubbly-slug flow, slug flow, slug-annular flow, and annular flow. A correlation for the bubble and slug diameter in the packed beds was proposed, which was an extended expression of the Tung/Dhir model, Jamialahmadi’s model, and Schmidt’s model. Three correlations were proposed to calculate the void friction of the flow pattern transition in bubble flow, slug flow, and annular flow based on the bubble model in the pore region. The experimental result showed that the modified Tung and Dhir model of the flow pattern transition was in better agreement with the experimental data compared with Tung and Dhir’s model.

Apparatus for automatically monitoring the distribution of gas flow over the cross section of a blast furnace top

Metallurgist ◽  
1970 ◽  
Vol 14 (6) ◽  
pp. 348-351
Author(s):  
V. A. Vanchikov ◽  
V. M. Antonov ◽  
Yu. I. Bulatov ◽  
V. M. Vinogradov ◽  
S. M. Dukarskii ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Cross Section ◽  
Gas Flow ◽  
The Cross

Patterns of Airflow in Circular Tubes Caused by a Corona Jet With Concentric and Eccentric Wire Electrodes

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Reza Baghaei Lakeh ◽  
Majid Molki
Keyword(s):  
Corona Discharge ◽  
Secondary Flow ◽  
Cross Section ◽  
Cross Sections ◽  
Method Of Characteristics ◽  
Numerical Solutions ◽  
Flow Patterns ◽  
Circular Tubes ◽  
The Method Of Characteristics ◽  
The Cross

A computational investigation is conducted to study the patterns of airflow induced by corona discharge in the cross section of a circular tube. The secondary flow induced by corona wind in various flow passages has been the subject of numerous investigations. The flow patterns are often identified by multiple recirculation bubbles. Such flow patterns have also been anticipated for circular cross sections where the corona discharge is activated by an electrode situated at the center of the cross section. In this investigation, it is shown that, contrary to public perception, a symmetric corona discharge does not generate a secondary flow in circular cross sections. This investigation then proceeds to demonstrate that the flow responsible for thermal enhancements in circular tubes often reported in the published literature is induced only when there is a slight asymmetry in the position of the electrode. The present computations are performed in two parts. In part one, the electric field equations are solved using the method of characteristics. In part two, the flow equations are solved using a finite-volume method. It is shown that the method of characteristics effectively eliminates the dispersion errors observed in other numerical solutions. The present computations show that the flow in the eccentric configuration is characterized by a corona jet that is oriented along the eccentricity direction and two recirculation zones situated on either sides of the jet. In addition to the computational approach, a number of analytical solutions are presented and compared with the computational results.

Numerical and Experimental Study of Multiphase Transient Core-Annular Flow Patterns in a Spouted Bed

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Ling Zhou ◽  
Chen Han ◽  
Ling Bai ◽  
Weidong Shi ◽  
Ramesh Agarwal
Keyword(s):  
Numerical Simulations ◽  
Flow Pattern ◽  
High Speed ◽  
Annular Flow ◽  
Fluid Phase ◽  
Flow Patterns ◽  
Spouted Bed ◽  
High Speed Imaging ◽  
Spouted Beds ◽  
Number Of Particles

Abstract Dense solid–gas bubbling systems with combined fluid-particle motion are among one of the most extensively used fluidization forms used in the chemical industry. Therefore, it is important to have a good understanding of the hydrodynamic behavior of bubbles. In this paper, both the experiment and numerical simulations are used to investigate the flow patterns in a spouted bed. For numerical simulations, the bidirectional coupling simulations using computational fluid dynamics (CFD) with discrete element method (DEM) are conducted. The results show that the simulations can accurately predict the bubbles morphology compared with the experimental results. When the number of particles is 30,000, only a single core-annular flow pattern appears. When the number of particles is increased to 36,500, the single bubble in the spouted bed transitions into two and a double core-annular flow pattern emerges. As the number of particles is increased to 43,000, a complex multicore-annular flow pattern appears. These flow patterns are also observed in the experiments using high-speed imaging camera. This paper analyzes and explains the causes of these flow phenomena from the dynamic characteristics of particle phase and fluid phase. These results have great significance in providing guidance for optimization of dense phase bubbling spouted beds.

The UGKS Simulation of Microchannel Gas Flow and Heat Transfer Confined Between Isothermal and Nonisothermal Parallel Plates

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Lianfu Dai ◽  
Huiying Wu ◽  
Jun Tang
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Gas Flow ◽  
Flow Direction ◽  
Channel Height ◽  
Parallel Plates ◽  
Gas Temperature ◽  
Gas Velocity ◽  
Microscopic Mechanism ◽  
Flow And Heat Transfer

Abstract The unified gas kinetic scheme (UGKS) is introduced to simulate the near transition regime gas flow and heat transfer in microchannel confined between isothermal and nonisothermal parallel plates. The argon gas is used and its inlet Knudsen number (Knin) ranges from 0.0154 to 0.0715. It is found that: (1) both microchannel gas flows under isothermal and nonisothermal parallel plates display a trend of speed acceleration and temperature decrease along flow direction, for which the microscopic mechanism explanation is first proposed; (2) inlet gas streamlines under nonisothermal plates condition deviate from the parallel distributions under isothermal plates condition due to the dual driving effects of pressure drop along flow direction and temperature difference along cross section; (3) gas temperature, pressure, density and viscosity distributions along cross section under nonisothermal plates condition deviate from the parabolic distributions under isothermal plates condition, while the gas velocity keeps the parabolic distribution due to the effect of Knudsen layer; (4) as channel height increases or channel length and gas molecular mean free path decrease, the gas temperature distribution along cross section under nonisothermal plates condition tends to transition from linear to curve one due to the decreasing effect of heat transfer along cross section and increasing effect of gas acceleration along flow direction, this transition from linear to curve one becomes more obvious along flow direction. (5) the gas velocity under nonisothermal plates condition decreases with the increase of inlet gas temperature (Tin), lower plate temperature (Tl) and Knin, while the gas temperature increases with the increase of Tin, Tl and Knin.

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