scholarly journals Study of Gas-Water Flow Inside of a Horizontal Passive Cyclonic Gas-Liquid Phase Separator System Using Displacement-Current Phase Tomography

2020 ◽  
Vol 6 (2) ◽  
pp. 28-43
Author(s):  
Joshua N. Sines ◽  
Benjamin J. Straiton ◽  
Christopher E. Zuccarelli ◽  
Qussai M. Marashdeh ◽  
Fernando L. Teixeira ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Water Flow ◽  
Flow Rate ◽  
Liquid Flow ◽  
Current Phase ◽  
Displacement Current ◽  
Air Flow Rate ◽  
Liquid Holdup ◽  
Flow Rates ◽  
Gas Liquid Flow

AbstractPassive cyclonic gas-liquid separators (PCGLSs) are commonly used in microgravity conditions where gravity settling separation is difficult or impossible. In this study, displacement-current phase tomography (DCPT) is used to measure various features of the gas-liquid flow inside of a PCGLS. The liquid holdup, liquid angular velocity, and gas core size are investigated. The liquid holdup is also measured in a gas-liquid flow that simulates the injection flow for a PCGLS. It is found that the gas core contracts and expands in a periodic motion as air is injected with water. This motion becomes more noticeable as the air flow rate is increased. It is also found that the liquid layer angular velocity has a positive linear trend with the air flow rate under constant water flow rates. A basic linear relation is derived to relate the liquid angular velocity to the air and water flow rates. All DCPT and electrical capacitance phase tomography (ECVT) results closely match the visual confirmation methods used for each flow feature.

Experiment Study of Pigging Characteristics in Horizontal Gas-Liquid Flow Pipeline With Different Pig Sizes

2012 ◽  
Author(s):  
Ruixi Duan ◽  
Da Yu ◽  
Haihao Wu ◽  
Jing Gong ◽  
Shanwei Hu ◽  
...  
Keyword(s):  
Water Flow ◽  
Liquid Flow ◽  
Pipe Wall ◽  
Flow Conditions ◽  
Experiment Study ◽  
Liquid Holdup ◽  
Long Distance ◽  
Inner Diameter ◽  
Gas Liquid Flow ◽  
The Relationship

During pigging process of long-distance pipeline, pig seals wear due to abrasion on pipe wall, the diameter of seal decreases and even to be smaller than pipe inner diameter as a result. This study has researched the characteristics of pigging processes using pigs different in diameter in horizontal experimental pipe. In the study, mandrel pig with two seals was chosen for experiment. Five pigs different in size were used, and pigging experiments under various flow conditions were carried out in a horizontal air-water flow experimental loop. During experiment, the features of pigging process from pig launcher to trap were observed, the liquid holdup and pressure were detected and collected, pig velocities in different sections of pipe were measured, the velocity of pigging slug front and length of the slug were also measured. The relationship between pig movement and flow conditions was analyzed, the methods to calculate velocity of pigging slug front and length of the slug were obtained and the results calculated were similar to the results measured. Based on the results of experiment, some suggestions were proposed for pigging operation in real pipeline.

Low-power micro-fabricated liquid flow-rate sensor

2015 ◽  
Vol 7 (9) ◽  
pp. 3981-3987 ◽  
Author(s):  
Wen-Chi Lin ◽  
Mark A. Burns
Keyword(s):  
Low Power ◽  
Water Flow ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Experimental Results ◽  
Flow Sensors ◽  
Flow Rates ◽  
Rate Sensor ◽  
Good Agreement

We have constructed micro-fabricated flow sensors that can measure water flow rates of 0.1 to 2.0 gallons per minute (GPM), and the experimental results we obtained are in good agreement with those from COMSOL simulations.

scholarly journals Experimental Study on Thermal Radiation Attenuation Using Water Mist of Twin-fluid Atomizer

2021 ◽  
Vol 35 (4) ◽  
pp. 24-32
Author(s):  
Jae Geun Jo ◽  
Chi Young Lee
Keyword(s):  
Thermal Radiation ◽  
Water Flow ◽  
Flow Rate ◽  
Air Flow ◽  
Water Flow Rate ◽  
Water Mist ◽  
Air Flow Rate ◽  
Radiation Attenuation ◽  
Rate Condition ◽  
Flow Rates

In this study, the thermal radiation attenuation performance of water mist was investigated using twin-fluid atomizers. The water and air flow rates of Small atomizer were 36~105 g/min and 10~30 L/min, whereas those of Large atomizer were 37~300 g/min and 20~60 L/min, respectively. In the present experimental range, the thermal radiation attenuation of Small atomizer and Large atomizer were 6.1~11.9% and 5.2~14.6%, respectively. With the increase in water and air flow rates, the thermal radiation attenuation increased, and under similar water and air flow rate conditions, Small atomizer showed higher thermal radiation attenuation than Large atomizer. Based on the present experimental data, it was found that the air (gas) discharge area is a potentially important factor in determining the thermal radiation attenuation performance. Additionally, through the analysis of thermal radiation attenuation per unit water flow rate, it was confirmed that the twin-fluid atomizer can result in higher thermal radiation attenuation than the single-fluid atomizer under the same water flow rate condition.

Experimental Study of Low Liquid Loading Gas-Liquid Flow in Near-Horizontal Pipes

2003 ◽  
Vol 125 (4) ◽  
pp. 294-298 ◽  
Author(s):  
Nicolas R. Olive ◽  
Hong-Quan Zhang ◽  
Qian Wang ◽  
Clifford L. Redus ◽  
James P. Brill
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Liquid Flow ◽  
Two Phase Flow ◽  
Liquid Density ◽  
Phase Flow ◽  
Liquid Holdup ◽  
Liquid Loading ◽  
Two Phase ◽  
Horizontal Pipes

Gas-liquid two-phase flow exists extensively in the transportation of hydrocarbon fluids. A more precise prediction of liquid holdup in near-horizontal, wet-gas pipelines is needed in order to better predict pressure drop and size downstream processing facilities. The most important parameters are pipe geometry (pipe diameter and orientation), physical properties of the gas and liquid (density, viscosity and surface tension) and flow conditions (velocity, temperature and pressure). Stratified flow and annular flow are the two flow patterns observed most often in near-horizontal pipelines under low liquid loading conditions. Low liquid loading is commonly referred to as cases in which liquid loading is less than 1,100m3/MMm3 (200 bbl/MMscf). Low liquid loading gas-liquid two-phase flow at −1° downward pipe was studied for air-water flow in the present study. The measured parameters included gas flow rate, liquid flow rate, pressure, differential pressure, temperature, liquid holdup, pipe wetted perimeter, liquid film flow rate, droplet entrainment fraction and droplet deposition rate. A new phenomenon was observed with air-water flow at low superficial velocities and with a liquid loading larger than 600m3/MMm3. The liquid holdup increased as gas superficial velocity increased. In order to investigate the effects of the liquid properties on flow characteristics, the experimental results for air-water flow are compared with the results for air-oil flow provided by Meng. (1999, “Low Liquid Loading Gas-Liquid Two-Phase Flow In Near-Horizontal Pipes,” Ph.D. Dissertation, U. of Tulsa.)

Experimental Analysis of Simplex Atomizer Spray and Swirling Flow Interactions in Unconfined Conditions

2015 ◽  
Author(s):  
Muthu Selvan ◽  
Muralidhara Suryanarayana Rao ◽  
Indu Kharb ◽  
Sundararajan Thirumalachari ◽  
Vinod Kumar Vyas ◽  
...  
Keyword(s):  
Size Distribution ◽  
Water Flow ◽  
Droplet Size ◽  
Flow Rate ◽  
Swirling Flow ◽  
Air Flow ◽  
Single Mode ◽  
Air Flow Rate ◽  
Volume Percentage ◽  
Flow Rates

An experimental study has been conducted to investigate the interaction between the conical spray produced by simplex atomizer and the swirling flow from an axial swirler. This work has been carried out in an unconfined ambience at isothermal conditions, using water. Malvern spray analyzer with a three dimensional traverse is used to characterize the swirling flow and spray interactions at various axial and radial locations. Images of spray at different conditions of air and water mass flow rates have been analyzed. Increasing the air mass flow through swirler at constant water flow rate, changes the spray structure significantly. These structural changes are sudden and highly dependent on the initial conditions of the spray. At smaller air flow rates, single-mode droplet size distribution at mid-plane changes into a bi-modal distribution at an air flow rate of about 35 kg/hr, with higher contribution of larger droplets. With further increase in air flow rate (90, 110 and 130 kg/hr), the bi-modal size distribution is maintained but with a larger volumetric fraction of small droplets. At different axial distances, the droplet size distributions are similar (single mode and bimodal distributions depending on air flow rate). But volume percentage of larger droplets is less compared to those of smaller droplets, at larger axial distance. At outer radial locations of the spray, volume percentage of larger droplets reduces and that of smaller droplets increases significantly, due to secondary droplet breakup. The interaction between the swirl and spray causes droplets to move radially outwards, resulting in droplet break-up by impact on the dome. Cases with higher air to water flow ratios exhibit significant changes in drop size distribution due to such swirl-spray interactions.

The effect of two-phase flow regime on hydrodynamics and mass transfer in a horizontal-tube gas-liquid reactor

1985 ◽  
Vol 50 (3) ◽  
pp. 745-757 ◽  
Author(s):  
Andreas Zahn ◽  
Lothar Ebner ◽  
Kurt Winkler ◽  
Jan Kratochvíl ◽  
Jindřich Zahradník
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Flow Regime ◽  
Liquid Flow ◽  
Horizontal Tube ◽  
Liquid Holdup ◽  
Two Phase ◽  
Flow Rates ◽  
Type Relation ◽  
Good Agreement

The effect of two-phase flow regime on decisive hydrodynamic and mass transfer characteristics of horizontal-tube gas-liquid reactors (pressure drop, liquid holdup, kLaL) was determined in a cocurrent-flow experimental unit of the length 4.15 m and diameter 0.05 m with air-water system. An adjustable-height weir was installed in the separation chamber at the reactor outlet to simulate the effect of internal baffles on reactor hydrodynamics. Flow regime maps were developed in the whole range of experimental gas and liquid flow rates both for the weirless arrangement and for the weir height 0.05 m, the former being in good agreement with flow-pattern boundaries presented by Mandhane. In the whole range of experi-mental conditions pressure drop data could be well correlated as a function of gas and liquid flow rates by an empirical exponential-type relation with specific sets of coefficients obtained for individual flow regimes from experimental data. Good agreement was observed between values of pressure drop obtained for weirless arrangement and data calculated from the Lockhart-Martinelli correlation while the contribution of weir to the overall pressure drop was well described by a relation proposed for the pressure loss in closed-end tubes. In the region of negligible weir influence values of liquid holdup were again succesfully correlated by the Lockhart-Martinelli relation while the dependence of liquid holdup data on gas and liquid flow rates obtained under conditions of significant weir effect (i.e. at low flow rates of both phases) could be well described by an empirical exponential-type relation. Results of preliminary kLaL measurements confirmed the decisive effect of the rate of energy dissipation on the intensity of interfacial mass transfer in gas-liquid dispersions.

scholarly journals Geometrical Optimization of a Venturi-Type Microbubble Generator Using CFD Simulation and Experimental Measurements

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 4
Author(s):  
Dillon Alexander Wilson ◽  
Kul Pun ◽  
Poo Balan Ganesan ◽  
Faik Hamad
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Air Flow ◽  
Bubble Diameter ◽  
Diameter Ratio ◽  
Experimental Measurements ◽  
Cfd Model ◽  
Flow Rates ◽  
Throat Diameter

Microbubble generators are of considerable importance to a range of scientific fields from use in aquaculture and engineering to medical applications. This is due to the fact the amount of sea life in the water is proportional to the amount of oxygen in it. In this paper, experimental measurements and computational Fluid Dynamics (CFD) simulation are performed for three water flow rates and three with three different air flow rates. The experimental data presented in the paper are used to validate the CFD model. Then, the CFD model is used to study the effect of diverging angle and throat length/throat diameter ratio on the size of the microbubble produced by the Venturi-type microbubble generator. The experimental results showed that increasing water flow rate and reducing the air flow rate produces smaller microbubbles. The prediction from the CFD results indicated that throat length/throat diameter ratio and diffuser divergent angle have a small effect on bubble diameter distribution and average bubble diameter for the range of the throat water velocities used in this study.

Model-Based Analysis of Transient Behavior of Large Scale CFB Boilers

2003 ◽  
Author(s):  
Ari Kettunen ◽  
Timo Hyppa¨nen ◽  
Ari-Pekka Kirkinen ◽  
Esa Maikkola
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Air Flow ◽  
Model Parameters ◽  
Air Flow Rate ◽  
Process Data ◽  
Cfb Boiler ◽  
Flow Rates ◽  
Load Change ◽  
Secondary Air

The main objective of this study was to investigate the load change capability and effect of the individual control variables, such as fuel, primary air and secondary air flow rates, on the dynamics of large-scale CFB boilers. The dynamics of the CFB process were examined by dynamic process tests and by simulation studies. A multi-faceted set of transient process tests were performed at a commercial 235 MWe CFB unit. Fuel reactivity and interaction between gas flow rates, solid concentration profiles and heat transfer were studied by step changes of the following controllable variables: fuel feed rate, primary air flow rate, secondary air flow rate and primary to secondary air flow ratio. Load change performance was tested using two different types of tests: open and closed loop load changes. A tailored dynamic simulator for the CFB boiler was built and fine-tuned by determining the model parameters and by validating the models of each process component against measured process data of the transient test program. The know-how about the boiler dynamics obtained from the model analysis and the developed CFB simulator were utilized in designing the control systems of three new 262 MWe CFB units, which are now under construction. Further, the simulator was applied for the control system development and transient analysis of the supercritical OTU CFB boiler.

scholarly journals Experimental Investigation on Improvement of Wet Cooling Tower Efficiency with Diverse Packing Compaction Using ANN-PSO Algorithm

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 167
Author(s):  
Hasan Alimoradi ◽  
Madjid Soltani ◽  
Pooriya Shahali ◽  
Farshad Moradi Kashkooli ◽  
Razieh Larizadeh ◽  
...  
Keyword(s):  
Neural Network ◽  
Water Temperature ◽  
Water Flow ◽  
Flow Rate ◽  
Cooling Tower ◽  
Air Flow ◽  
Water Flow Rate ◽  
Pso Algorithm ◽  
Outlet Temperature ◽  
Air Flow Rate

In this study, a numerical and empirical scheme for increasing cooling tower performance is developed by combining the particle swarm optimization (PSO) algorithm with a neural network and considering the packing’s compaction as an effective factor for higher accuracies. An experimental setup is used to analyze the effects of packing compaction on the performance. The neural network is optimized by the PSO algorithm in order to predict the precise temperature difference, efficiency, and outlet temperature, which are functions of air flow rate, water flow rate, inlet water temperature, inlet air temperature, inlet air relative humidity, and packing compaction. The effects of water flow rate, air flow rate, inlet water temperature, and packing compaction on the performance are examined. A new empirical model for the cooling tower performance and efficiency is also developed. Finally, the optimized performance conditions of the cooling tower are obtained by the presented correlations. The results reveal that cooling tower efficiency is increased by increasing the air flow rate, water flow rate, and packing compaction.

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