Experimental Measurement of Interfacial Parameters of Elongated Bubbles in Two Phase Gas-Liquid Flow in Horizontal and Slightly Inclined Circular Pipes

2010 ◽  
Author(s):  
J. S. Cunha Filho ◽  
J. L. H. Faccini ◽  
C. A. Lamy ◽  
J. Su
Keyword(s):  
High Speed ◽  
Digital Camera ◽  
Superficial Velocity ◽  
Digital Data ◽  
Visualization Technique ◽  
Two Phase ◽  
Analog Signals ◽  
Circular Pipes ◽  
Gas Liquid Flow ◽  
Good Agreement

This paper reports an experimental study of the measurement of elongated bubbles velocities and their longitudinal shapes using a high speed ultrasonic system in concurrent horizontal and at 5° and 10° inclined upward flow. The circular pipe test section is made of 25.6 mm stainless steel, followed by a transparent acrylic pipe with the same diameter. The high speed ultrasonic system consists of two transducers (10 MHz/6.35 mm diameter), a generator/multiplexer board that convert analog signals into digital data at a rate of 100 million frames per second, and a software that stores all the frames and the results of the time of flight of each signal. The results are compared with a visualization technique that consists of a high-speed digital camera recording images at rates of 125 and 250 frames per second. This range of liquid superficial velocity is from 0.2 to 1.1 m/s and that of the gas superficial velocity is from 0.35 to 1.0 m/s. The results obtained with the two experimental techniques show a good agreement among them for the elongated bubbles lengths and velocities, while having great statistics dispersion. The measured bubble shape is in agreement with literature data.

Effect of Pressure on Bubble Growth Within Liquid Droplets at the Superheat Limit

1982 ◽  
Vol 104 (4) ◽  
pp. 750-757 ◽  
Author(s):  
C. T. Avedisian
Keyword(s):  
Vapor Bubble ◽  
Bubble Growth ◽  
High Speed ◽  
Ambient Pressure ◽  
Organic Liquid ◽  
Liquid Droplets ◽  
Growth Data ◽  
Two Phase ◽  
Photographic Evidence ◽  
Good Agreement

A study of high-pressure bubble growth within liquid droplets heated to their limits of superheat is reported. Droplets of an organic liquid (n-octane) were heated in an immiscible nonvolatile field liquid (glycerine) until they began to boil. High-speed cine photography was used for recording the qualitative aspects of boiling intensity and for obtaining some basic bubble growth data which have not been previously reported. The intensity of droplet boiling was found to be strongly dependent on ambient pressure. At atmospheric pressure the droplets boiled in a comparatively violent manner. At higher pressures photographic evidence revealed a two-phase droplet configuration consisting of an expanding vapor bubble beneath which was suspended a pool of the vaporizing liquid. A qualitative theory for growth of the two-phase droplet was based on assuming that heat for vaporizing the volatile liquid was transferred across a thin thermal boundary layer surrounding the vapor bubble. Measured droplet radii were found to be in relatively good agreement with predicted radii.

Experimental Determination of Hydrodynamic Parameters of Air-Water Two-Phase Slug Flow in Horizontal Pipes

2012 ◽  
Author(s):  
Carlos H. Romero ◽  
María A. Márquez ◽  
Sissi D. Vergara ◽  
María T. Valecillos
Keyword(s):  
Slug Flow ◽  
High Speed ◽  
Electronic Device ◽  
Water System ◽  
Superficial Velocity ◽  
Two Phase ◽  
Horizontal Pipes ◽  
Type Pattern ◽  
Elongated Bubble

Two phase slug flow is the most common flow pattern for horizontal and near-horizontal pipelines. This study is designed to determine experimental velocities of elongated bubbles, lengths of liquid slugs and elongated bubbles, and slug frequencies for twenty flow rates combinations of a two phase air-water system that belong to a slug type pattern in horizontal pipes with a non invasive electronic device made of Photo-diodes (emitter) and photo-transistors (receiver) in a non visible length wave of 940 nanometers. The non intrusive electronic device is validated by simultaneously taking pictures with a high speed camera, (Kodak model Ektapro 4540 mx Imager, at shooting speed of 4500 frames per second, the picture resolution is 256 × 256 pixels), through a visualization cell filled with glycerin. This work is done with acrylic pipes of 0,03175 m inner diameter, to ensure complete flow development, the pictures are taken from a visualization cell located at a x/D = 249, the electronic device is located at x/D = 250. Air superficial velocity ranged between 0.156 and 0.468 m/s while water superficial velocity ranged between 0.159 and 1.264m/s. It is found that the non intrusive electronic device formed by photo diodes and photo transistors is an accurate technique that can be used in the determination of elongated bubble velocities, lengths and slug frequencies.

Unified Model for Gas-Liquid Pipe Flow Via Slug Dynamics: Part 2 — Model Validation

2002 ◽  
Author(s):  
Hong-Quan Zhang ◽  
Qian Wang ◽  
Cem Sarica ◽  
James P. Brill
Keyword(s):  
Experimental Data ◽  
Liquid Flow ◽  
Pipe Flow ◽  
Flow Behavior ◽  
Two Phase ◽  
Flow Rates ◽  
Inclination Angles ◽  
Gas Liquid Flow ◽  
Extensive Experimental Data ◽  
Good Agreement

In Zhang et al. [1], a unified hydrodynamic model is developed for prediction of gas-liquid pipe flow behavior based on slug dynamics. In this study, the new model is validated with extensive experimental data acquired with different pipe diameters, inclination angles, fluid physical properties, gas-liquid flow rates and flow patterns. Good agreement is observed in every aspect of the two-phase pipe flow.

scholarly journals IMPLEMENTATION OF A REDUCED COMPLEXITY HIGH PERFORMANCE DATA ACQUISITION CHIP USING 0.18 MICRON TECHNOLOGY

2021 ◽  
Vol 7 (3) ◽  
pp. 22-26
Author(s):  
Hai P. Le ◽  
◽  
Aladin Azyegh ◽  
Jugdutt Singh ◽  
◽  
...  
Keyword(s):  
Low Power ◽  
Data Acquisition ◽  
High Speed ◽  
High Performance ◽  
Modern Science ◽  
Digital Data ◽  
Clock Frequency ◽  
Flash Adc ◽  
Analog Signals ◽  
Wide Range

Data acquisition (DAQ) in the general sense is the process of collecting information from the real world. For engineers and scientists, this data is mostly numerical and is usually collected, stored and analysed using computers. However, most of the input signals cannot be read directly by digital computers. Because they are generally analog signals distinguished by continuous values, while computers can only recognise digital signals containing only the on/off levels. DAQ systems are therefore inevitably necessary, as they include the translation requirements from analog signals to digital data. For this reason, they have become significant in wide range of applications in modern science and technology [1]. The paper precents the disign of a 12-bit high-speed low-power Data Acquisition (DAQ) Chip. In this paper, the disigns of the building block components are aimed at high-accuracy along with high-speed and low power dissipation. A modifided flash Analog-to-Digital converter (ADC) was used instead of the traditional flash proposed DAQ chip operates at 1 GHz master clock frequency and achieves a sampling speed of 125 MS/s. It dissipates only 64.9 mW of power as compared to 97.2 mW when traditional flash ADC was used.

Analysis of Liquid Slug Motion in a Voided Line

1998 ◽  
Vol 120 (1) ◽  
pp. 74-80 ◽  
Author(s):  
J. Yang ◽  
D. C. Wiggert
Keyword(s):  
Momentum Transfer ◽  
High Speed ◽  
Time History ◽  
Air Entrainment ◽  
Phase Flow ◽  
Liquid Slug ◽  
Two Phase ◽  
Pressure Time ◽  
History Of ◽  
Good Agreement

A quasi-two-dimensional two-phase flow cylindrical model of slug motion in a voided line is developed that can reasonably predict the change of flow pattern of the slug, air entrainment, “holdup” and the distribution of axial velocity. However, when using the theory of incompressible momentum transfer to estimate the pressure-time history of slug at the elbow, the calculated results are not in good agreement with those of the experiments. Further analysis of the experimental results indicate that an acoustic, or waterhammerlike response may occur immediately upon impact of the high-speed slug with the elbow, and subsequently, the waveform exhibits momentum transfer due to the acceleration of the slug at the elbow.

Correlation between Void Fraction and Two-Phase Flow Pattern Air-Water with Low Viscosity in Mini Channel with Slope 30 Degrees

2020 ◽  
Vol 846 ◽  
pp. 289-295
Author(s):  
Sukamta ◽  
Sudarja
Keyword(s):  
Void Fraction ◽  
High Speed ◽  
Two Phase Flow ◽  
Fluid Velocity ◽  
Flow Patterns ◽  
Superficial Velocity ◽  
Working Fluid ◽  
Phase Flow ◽  
Two Phase ◽  
Void Fractions

Two-phase flow has been used in so many industrial processes, such as boilers, reactors, heat exchangers, geothermal and others. Some parameters which need to be studied include flow patterns, void fractions, and pressure changes. Research on void fractions aims to determine the composition of the gas and liquid phases that will affect the nature and value of the flow property. The purpose of this study is to find out the characteristics of the void fraction of various patterns that occurs and to determine the characteristics of the velocity, length, and frequency of bubbly and plug. Data acquisition was used to convert the data from analog to digital so that it can be recorded, stored, processed, and analyzed. High-speed camera Nikon type J4 was used to record the flow. The condition of the study was adiabatic with variation of superficial gas velocity (JG), superficial fluid velocity (JL), and also working fluid. To determine the void fraction by using the digital image processing method. The results of the study found that the flow patterns which occurred in this study were bubbly, plug, annular, slug-annular and churn flows. It also showed that the void fraction value is determined by the superficial velocity of the liquid and air. The higher the superficial velocity of the air, the lower the void fraction value.

CFD Simulation Study of Gas-Liquid Flow Regimes in Inclined Wellbore

2014 ◽  
Vol 915-916 ◽  
pp. 126-130
Author(s):  
Yin Di Zhang ◽  
Long Fei Ruan ◽  
De Hua Liu
Keyword(s):  
Inclination Angle ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Flow Regimes ◽  
Two Phase ◽  
Flow Rates ◽  
Flow Regime Transition ◽  
Gas Liquid Flow ◽  
Cfd Method ◽  
Good Agreement

Computational Fluid Dynamic (CFD) was used to investigate gas-liquid two phase flow regimes for the inclined wells. The simulation results were compared with the Taitel chart. A good agreement between the prediction and the Taitel flow regimes shows that CFD method can reasonably predict flow regimes in the inclined well. Another further study was conducted to explore the influence of flow rates and inclination angle on flow regimes. The results show both of flow rates and inclination angle have a significant effect on flow regime transition.

Experimental Study Structure Of Gas-Liquid Flow In Rectangular Minichannel By Optical Methods

2015 ◽  
Vol 10 (3) ◽  
pp. 63-69
Author(s):  
Igor Kozulin ◽  
Vladimir Kuznetsov
Keyword(s):  
Liquid Flow ◽  
High Speed ◽  
Laser Scanning ◽  
Rectangular Channel ◽  
Optical Methods ◽  
Statistical Characteristics ◽  
Transition Flow ◽  
Two Phase ◽  
Beam Laser ◽  
Gas Liquid Flow

In this paper, using method of two-beam laser scanning and high-speed video was identified patterns of distribution phases in the cross-section of the rectangular channel 0.72 × 1.50 mm with hydraulic diameter of the order to capillary constant. The structure of the gas-liquid flow was studied including flow regimes and statistical characteristics of the two-phase flow in regime with elongated bubbles, transition flow and annular flow regime.

Experimental Investigation of the Two-Phase Phenomena in a Small Discharge Installed on a Large Pipe With Stratified Gas-Liquid Flow

2009 ◽  
Author(s):  
Robert Bowden ◽  
Wael F. Saleh ◽  
Ibrahim Hassan
Keyword(s):  
Experimental Investigation ◽  
Flow Visualization ◽  
Flow Rate ◽  
Liquid Flow ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Gas Entrainment ◽  
Small Discharge ◽  
Gas Liquid Flow ◽  
Good Agreement

Experiments were performed in a 50.8 mm diameter horizontal pipe with co-current stratified gas-liquid flow. A single, 6.35 mm diameter, downward oriented discharge was located at 1829 mm from the horizontal pipe’s inlet. Water and air, operating at a pressure of 312 kPa and adiabatic conditions, were used. The objectives of the study were to investigate gas entrainment in the discharge branch. Qualitative flow visualization of the two-phase entrainment flow structure was conducted, and measurements of the critical liquid height, two-phase mass flow rate, and quality, are provided. The results were compared with available correlations and showed good agreement with selected models.

Two-Phase Slug Flow in a Narrow Rectangular Channel Under Inclined Conditions

2014 ◽  
Author(s):  
Yang Wang ◽  
Changqi Yan ◽  
Licheng Sun ◽  
Chaoxing Yan ◽  
Yanmin Zhou ◽  
...  
Keyword(s):  
Slug Flow ◽  
High Speed ◽  
Rectangular Channel ◽  
Video Camera ◽  
Superficial Velocity ◽  
Bubble Velocity ◽  
Two Phase ◽  
Camera System ◽  
Taylor Bubble ◽  
Inclination Angles

The characteristics of two-phase slug flow in a narrow rectangular channel with cross section of 3.25 mm × 43 mm under vertical and inclined conditions are investigated using a high speed video camera system. It is found that the velocity of Taylor bubble in vertical continuous slug flow could be well predicted by the Nicklin et al. (1962) correlation, in which C0 is given by the correlation of Ishii (1977), and the drift velocity given by the correlation of Sadatomi et al. (1982) or Clanet et al. (2004). For low two-phase superficial velocity (FrTP ≤ 3.5), the Taylor bubble velocities gradually increase with the increasing in inclination angles and almost approximate the maximum value for θ = 30°. For high two-phase superficial velocity (FrTP > 3.5), the influence of the inclination angles on the Taylor bubble velocity is insignificant, and the bubble velocity under vertical condition is slight lower than those under inclined conditions. For the inclined cases, the nose of Taylor bubble is deviated from the centerline and its position is the function of the two-phase superficial velocity as well as the inclination angle.

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