Journal articles: 'Superficial air velocity'

1

Bamufleh, Hesham S., S. A. Nosier, and M. A. Daous. "Characteristics of Liquid–Solid Mass Transfer in a Bubble Column Equipped with a Vertical Tube of Circular Fins." Defect and Diffusion Forum 312-315 (April 2011): 647–52. http://dx.doi.org/10.4028/www.scientific.net/ddf.312-315.647.

Full text

Abstract:

The solid-liquid mass transfer rate at a stack of circular fin surfaces in a bubble column was investigated. A diffusion-controlled dissolution technique of copper in an acidified chromate solution was employed. Variables studied included the number of actively exposed fins ranging from 5 to 20, pertinent physical properties of the solution, and air superficial velocity. Experimental data showed that the rate of the diffusion-controlled mass transfer increases with increasing superficial air velocity and decreases with increasing chromate solution acid concentration. Moreover, at relatively low superficial air velocity, increasing the number of actively exposed fins results into a continuous increase in the mass transfer coefficient. At relatively higher superficial air velocity, however, the mass transfer coefficient decreases in the 5 to 10 range of actively exposed fins and then reverts to increase in the 15 to 20 range.

APA, Harvard, Vancouver, ISO, and other styles

2

Zhang, Ruijie, Fangfang Tao, Haibo Jin, Xiaoyan Guo, Guangxiang He, Lei Ma, Rongyue Zhang, Qingyang Gu, and Suohe Yang. "Effect of Liquid Properties on Frictional Pressure Drop in a Gas-Liquid Two-Phase Microchannel." Processes 10, no. 5 (April 19, 2022): 799. http://dx.doi.org/10.3390/pr10050799.

Full text

Abstract:

The flow characteristics in a ring-shaped microchannel with an inner diameter of 1 mm were studied in two-phase flow systems with air-water, air-glycerol aqueous solution and air-ethanol aqueous solution using the differential pressure method. The effects of liquid properties (surface tension and viscosity) and gas/liquid superficial velocity on frictional pressure drop were discussed. The experimental results show that the frictional pressure gradient increases with the increase of superficial gas velocity, superficial liquid velocity and liquid viscosity, and increases with the decrease of liquid surface tension, which has a good agreement with the literature values. The friction pressure drop data are compared with the classical models and correlations in literature, and a reliable correlation is proposed for prediction of two-phase friction coefficient in microchannels.

APA, Harvard, Vancouver, ISO, and other styles

3

Memon, Z. Q., W. Pao, F. Hashim, and S. Ahmed. "Experimental investigation of multiphase separation in different flow regimes through T-junction with an expander section." Journal of Mechanical Engineering and Sciences 13, no. 2 (June 28, 2019): 5163–81. http://dx.doi.org/10.15282/jmes.13.2.2019.27.0424.

Full text

Abstract:

The experimental data for phase separation of the air-water mixture in a T-Junction with the expander section after the branch arm is presented in this work. The main and run arms of the T-junction are directed along the horizontal plane with the branch arm positioned in the vertical plane. The diameter of the main arm is 74 mm, with diameter ratio(s) of, 0.67, and 0.33 in relation to branch arm. At the inlet section of the T-junction, the flow regimes generated were stratified, stratified wavy and slug flow. At the inlet, the air and water superficial velocities are in the range of 0.25 - 0.140 m/s and 0.14-0.78 m/s respectively. The effect of the expander section after the branch arm, the air superficial velocity USA and water superficial velocity USw on liquid carryover (WL3/WL1)max in branch arm have been studied. Based on the experimental data obtained for T-junction with expander section, complete phase separation of air and water was observed in stratified and stratified wavy flow for all superficial velocities and improved phase separation for slug flow. In slug flow, increasing the liquid superficial velocity improves the phase separation but increasing the gas velocity decreases the phase separation. Finally, the volume weighted phase in this new T-junction design is compared with the phase separation data of a simple T-junction.

APA, Harvard, Vancouver, ISO, and other styles

4

Zhou, Yun Long, and Ning Yang. "Riser Pipe Pressure Pulsation Standard Deviation Fast Forecast Spouted Bed Granular Poly Group." Applied Mechanics and Materials 448-453 (October 2013): 3397–402. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.3397.

Full text

Abstract:

At the different elevation of the spouted bed riser pipe layout pressure measuring point, each point below is equipped with purge air, avoid the granular poly group on the pressure measuring point, by adjusting the frequency of the bandpass filter, guarantee the accuracy of pressure measurement. Through experimental study, under the low superficial air velocity, riser pipe pressure pulsation standard deviation has a linear relationship with the superficial air velocity and obey the chi-square distribution, based on the above found , rising pipe pressure pulsation standard deviation forecast the incidence of granular poly group is proposed in this paper. By comparing rising pipe pressure pulsation standard deviation forecast method with conventional average pressure drop forecast method found, rising pipe pressure pulsation standard deviation has higher superficial air velocity recognition rate and less response time when the granular poly group,achieves the spouted bed fast forecast the granular poly group phenomenon.

APA, Harvard, Vancouver, ISO, and other styles

5

Li, Ting, Wen Yi Dong, Hong Jie Wang, Jin Nan Lin, Feng Ouyang, and Qian Zhang. "Particles Capturing and Correlation with Head Loss in a Pilot-Scale Biological Aerated Filter." Applied Mechanics and Materials 409-410 (September 2013): 279–86. http://dx.doi.org/10.4028/www.scientific.net/amm.409-410.279.

Full text

Abstract:

Experimental observations of particle capturing through the biological aerated filter bed indicated that air flow rate plays an important role in head loss development by influencing the suspended solids distribution along the depth of the bed as well as the morphology of the deposits. The active height for the SS removal prolonged with the increasing of the air velocity based on the mechanism of first-order kinetics. With the increasing of the superficial air velocity, the effluent SS concentration and the time need to reach the stead-states after backwash both increased. The value of the SS spike in the effluent after backwash at superficial air velocity of 27 m/hr was nearly twice as much as that of 5.4m/hr. Distribution of the deposits at higher air velocity was more uniform. Deposits at lower velocity with air flow rate produced higher head loss gradient. The headloss increased with the increasing of deposits and the increase rate was faster when the deposits exceeded higher value.

APA, Harvard, Vancouver, ISO, and other styles

6

Hanna, Fadi Z., and Ihsan B. Hamawand. "Bubbles Coalescence Frequency and Transition Concentration in Bubble Column." Tikrit Journal of Engineering Sciences 13, no. 4 (December 31, 2006): 73–95. http://dx.doi.org/10.25130/tjes.13.4.04.

Full text

Abstract:

Bubbles coalescence frequency and the transition concentration in a dispersion column were studied experimentally by using ethanol-water mixture as a liquid phase and air as a gas phase. The study was devoted to express the effect of the liquid properties on the performance of the dispersion column, and the experimental work was designed for this purpose, where the range of weight percent of ethanol in water, (0.1-0.7) Wt%, and the range of superficial gas velocity of air, (2.5-30) mm/s. The experimental runs were planned using the central composite routable design method. The experimental data obtained agreed quite well with a polynomial type of correlations by using computer program. The experimental data shows that the values of bubble coalescence decrease with increasing superficial gas velocity of air, and ethanol transition concentration was successfully correlated as a function of the superficial gas velocity of air, ct= 0.158214 − 0.010849Ug + 0.00045Ug2 − 0.000008Ug3 . This equation gives mean deviation of 10.393%.

APA, Harvard, Vancouver, ISO, and other styles

7

Liu, Xue Min, Zhou Hang Li, Yu Xin Wu, and Jun Fu Lu. "Effect of Tube Size on Flow Pattern of Air-Water Two-Phase Flow in Horizontal Tubes." Advanced Materials Research 746 (August 2013): 575–80. http://dx.doi.org/10.4028/www.scientific.net/amr.746.575.

Full text

Abstract:

Aiming at the diameter range of boiler water wall tubes in practical engineering application, the air-water two phase flow pattern in horizontal tube was experimentally investigated in tubes with different inner diameters of 20mm and 8 mm under atmosphere condition. The stratified flow, wave flow, plug flow, slug flow, annular flow, bubbly flow and mist flow were observed in the tubes. Most of the experimental points agree well with the Baker flow pattern map when they appear in the map. With the experimental results, the range lines between the flow patterns were suggested for the tube of 20mm in inner diameter as well as 8mm. As the water superficial velocity increases, the annular flow transforms into mist flow at a decreasing air superficial velocity. The two phase flow patterns transition line is similar in tendency for different tubes. The slug flow transforms into annular flow at an increasing air superficial velocity as tube diameter decreases. The stratified flow transforms into slug flow at an increasing water superficial velocity as tube diameter decreases. The transition line between plug flow and slug flow is independent of tube diameter.

APA, Harvard, Vancouver, ISO, and other styles

8

Osokogwu, Uche. "Effects of Liquid Velocity on Pressure Gradient, Slip and Interfacial Friction Factor in Annular Flow in Horizontal Pipe." European Journal of Engineering Research and Science 3, no. 8 (August 8, 2018): 5. http://dx.doi.org/10.24018/ejers.2018.3.8.819.

Full text

Abstract:

Experimental investigations on annular flow behaviour in two-phase (air/water) flow in horizontal pipe were conducted using 2-inch (0.0504m) with a total length of 28.68m closed loop system. The emphasis from the experiments were on pressure gradient, slip and interfacial friction factor in annular flow. For interfacial friction factor, the entrainment, gas quality, the droplets and slip mixture density values were obtained through the experimental results which were substituted to determine it. In all, effects of liquid velocity were felt, as increase in superficial liquid velocity, increases the interfacial friction factor and pressure gradient in annular flow in horizontal pipes. More so, increase in superficial gas velocity, reduces the interfacial friction factor. Thus, interfacial friction factor decreases with increases in superficial gas velocity, while the pressure gradient increases with increase in superficial liquid velocity. The lower the superficial liquid velocity, the higher the slip but the lower the pressure gradient. Likewise, the lower the superficial liquid velocity, the more ripple waves obtained while the higher the superficial liquid velocity, the more disturbance waves in annular flow in horizontal pipe from the experiments.

APA, Harvard, Vancouver, ISO, and other styles

9

Osokogwu, Uche. "Effects of Liquid Velocity on Pressure Gradient, Slip and Interfacial Friction Factor in Annular Flow in Horizontal Pipe." European Journal of Engineering and Technology Research 3, no. 8 (August 8, 2018): 5–11. http://dx.doi.org/10.24018/ejeng.2018.3.8.819.

Full text

Abstract:

Experimental investigations on annular flow behaviour in two-phase (air/water) flow in horizontal pipe were conducted using 2-inch (0.0504m) with a total length of 28.68m closed loop system. The emphasis from the experiments were on pressure gradient, slip and interfacial friction factor in annular flow. For interfacial friction factor, the entrainment, gas quality, the droplets and slip mixture density values were obtained through the experimental results which were substituted to determine it. In all, effects of liquid velocity were felt, as increase in superficial liquid velocity, increases the interfacial friction factor and pressure gradient in annular flow in horizontal pipes. More so, increase in superficial gas velocity, reduces the interfacial friction factor. Thus, interfacial friction factor decreases with increases in superficial gas velocity, while the pressure gradient increases with increase in superficial liquid velocity. The lower the superficial liquid velocity, the higher the slip but the lower the pressure gradient. Likewise, the lower the superficial liquid velocity, the more ripple waves obtained while the higher the superficial liquid velocity, the more disturbance waves in annular flow in horizontal pipe from the experiments.

APA, Harvard, Vancouver, ISO, and other styles

10

Milivojevic, Milan, Aleksandar Dudukovic, Bojana Obradovic, Aleksandar Spasic, and Branko Bugarski. "Analysis of the hydrodynamic parameters of external loop air lift bioreactors." Chemical Industry 58, no. 1 (2004): 10–18. http://dx.doi.org/10.2298/hemind0401010m.

Full text

Abstract:

In this study we analyzed the effects of the hydrodynamic conditions and properties of the working fluid on the operation of external loop air lift bioreactors. In particular, the effects of design and operating parameters (e.g. reactor geometry, design of the gas sparger, superficial gas velocity, flow regime) as well as the fluid properties (liquid viscosity and addition of surfactants) on the liquid superficial velocity and gas hold-up were defined. Several correlations found in the literature based on theoretical models of fluid flow, as well as several semi-empirical and empirical correlations were tested and the applicability of all the proposed correlations was verified on the available experimental data. The most accurate correlations for the prediction of the gas hold up, liquid circulation velocity and slip velocity in each bioreactor operating regime were identified.

APA, Harvard, Vancouver, ISO, and other styles

11

Shen, Zhi Yuan, Li Jun Yang, Meng Xi Liu, Chun Xi Lu, and Xiao Na Liu. "Particle Velocity Distribution in a Novel Draft Tube-Lifted Gassolid Air Loop Reactor." Advanced Materials Research 396-398 (November 2011): 639–47. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.639.

Full text

Abstract:

The hydrodynamics in a gas-solid draft tube-lifted air-loop reactor (GSALR) was investigated systematically using experimental measurements. To demonstrate the gas-solid flow pattern, the upward particle velocity, downward particle velocity and time-averaged particle velocity in four regions of the GSALR were measured by optical fiber probe under different superficial gas velocities. The experimental results show that the downward particle velocity distributes uniformly along the radius in the four regions, but the radial distributions of upward particle velocity and time-averaged particle velocity are core-annulus or heterogeneous structure in the three regions (distributor affect region, draft tube, gas-solid diffluence region), which have the common feature of aggregative fluidization occurred in normal fluidized beds. The operating condition such as superficial gas velocity in draft tube has different effects on the radial distributions of upward particle velocity, downward particle velocity and time-averaged particle velocity in each region. Analysis of the distributions of upward particle velocity, downward particle velocity and time-averaged particle velocity leads to suggestions regarding optimization of the design and provides further theoretical basis for industry application of GSALR.

APA, Harvard, Vancouver, ISO, and other styles

12

Tran, Minh, Zeeshan Memon, Ahmed Saieed, William Pao, and Fakhruldin Hashim. "Numerical simulation of two-phase separation in T-junction with experimental validation." Journal of Mechanical Engineering and Sciences 12, no. 4 (December 27, 2018): 4216–30. http://dx.doi.org/10.15282/jmes.12.4.2018.17.0363.

Full text

Abstract:

Liquid carryover in T-junction due to splitting nature of two-phase flow causes serious issues for downstream equipment which is not designed to handle excessive liquid. In this paper, the phenomena of liquid carryover in T-junctions were analyzed using the Volume of Fraction (VOF) together with the k-ε turbulence model. T-junction separation efficiency was measured through mass flow rate fraction of air and water between the branch and main arm over a range of diameter ratios 0.6 to 1.0, water superficial velocity 0.186 to 0.558 m/s and air superficial velocity 4 to 8 m/s. The results showed simulation model was successfully validated with average deviation of less than 5% and can be used to predict phase split of slug flow in T-junction. The numerical model confirmed the significant influence of diameter ratio and superficial velocities of air and water on phase split. Reduced T-junction delivers better separation performance compared to regular T-junction. In slug flow regime, T-junction’s performance can be improved by either decreasing air velocity or increasing water velocity. A new dimensionless parameter, namely the area under the curve of separation efficiency (S), was proposed and proved as a qualified judging criteria for evaluating phase separation efficiency of T-junctions.

APA, Harvard, Vancouver, ISO, and other styles

13

Sovilj, Milan. "Axial Dispersion in a Three-Phase Gas-Agitated Spray Extraction Column." Collection of Czechoslovak Chemical Communications 63, no. 2 (1998): 283–92. http://dx.doi.org/10.1135/cccc19980283.

Full text

Abstract:

The continuous-phase axial dispersion coefficients of the three-phase gas-liquid-liquid system in a gas-agitated spray extraction column 10 cm i.d. at 20 °C were examined. The system used was water as continuous phase, toluene as dispersed phase, and air as gaseous phase. The rise in the gas phase superficial velocity increased the continuous-phase axial dispersion coefficient. A non-linear dependence between the continuous-phase axial dispersion coefficient and the continuous phase superficial velocity was observed. No correlation was found between the continuous-phase axial dispersion coefficient and dispersed phase superficial velocity. The increase in the gas phase hold-up corresponded to a slight increase in the continuous-phase axial dispersion coefficient. The increase in the dispersed phase hold-up generated a growth of the continuous-phase axial dispersion coefficient. A comparison was made of the continuous-phase axial dispersion coefficients of the three-phase (air-water-toluene) and two-phase (water-toluene) systems.

APA, Harvard, Vancouver, ISO, and other styles

14

Sukamta and Sudarja. "Correlation between Void Fraction and Two-Phase Flow Pattern Air-Water with Low Viscosity in Mini Channel with Slope 30 Degrees." Key Engineering Materials 846 (June 2020): 289–95. http://dx.doi.org/10.4028/www.scientific.net/kem.846.289.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

15

Gheni, Saba A., Yasser I. Abdulaziz, and Muthanna H. Al-Dahhan. "Effect of L/D Ratio on Phase Holdup and Bubble Dynamics in Slurry Bubble Column using Optical Fiber Probe Measurements." International Journal of Chemical Reactor Engineering 14, no. 2 (April 1, 2016): 653–64. http://dx.doi.org/10.1515/ijcre-2015-0035.

Full text

Abstract:

Abstract In this investigation, time average local gas holdup and bubble dynamic data were achieved for three L/D ratios of slurry bubble column. The examined ratios were 3, 4 and 5 in 18″ diameter slurry bubble column. Air-water-glass bead system was used with superficial gas velocity up to 0.24 m/s. The gas holdup was measured using four tips optical fiber probe technique. The results showed that the gas holdup increases almost linearly with the superficial gas velocity in 0.08 m/s and levels off with a further increase of velocity. A comparison of the present data with those reported for other slurry bubble column having diameters greater than 18″ and L/D higher than 5 was made. The results indicated a little effect of diameter on the gas holdup. A local, section-averaged gas holdup increases with increasing superficial gas velocity, while the effect of solid loading are less significant than that of the superficial gas velocity. Chaos analysis was used to analyze the slurry system.

APA, Harvard, Vancouver, ISO, and other styles

16

Liu, Zilong, Yubin Su, Ming Lu, Zilong Zheng, and Ruiquan Liao. "Frictional Pressure Drop and Liquid Holdup of Churn Flow in Vertical Pipes with Different Viscosities." Geofluids 2021 (January 26, 2021): 1–8. http://dx.doi.org/10.1155/2021/6661014.

Full text

Abstract:

Churn flow commonly exists in the pipe of heavy oil, and the characteristics of churn flow should be widely understood. In this paper, we carried out air and viscous oil two-phase flow experiments, and the diameter of the test section is 60 mm. The viscosity range of the oil was 100~480 mPa·s. Based on the measured liquid holdup and pressure drop data of churn flow, it can be concluded that, due to the existence of liquid film backflow, positive and negative frictional pressure drop can be found and the change of frictional pressure drop with the superficial gas velocity is related to superficial liquid velocity. With the increase of viscosity, the change rate of frictional pressure drop increases with the increase of the superficial gas velocity. Combining our previous work and the Taitel model, we proposed a new pressure drop model for viscous oil-air two-phase churn flow in vertical pipes. By comparing the predicted values of existing models with the measured pressure drop data, the proposed model has better performance in predicting the pressure drop.

APA, Harvard, Vancouver, ISO, and other styles

17

Apip Badarudin, Andriyanto Setyawan, and Windy Hermawan Mitrakusuma. "Void Fraction and Flow Pattern of R-290 in A Horizontal Evaporator: Effects of Pipe Diameter and Cooling Capacity." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 85, no. 1 (July 29, 2021): 40–53. http://dx.doi.org/10.37934/arfmts.85.1.4053.

Full text

Abstract:

Void fraction and flow pattern play important roles in the performance of evaporator in an air conditioning system. In this paper, the behaviors of void fraction and flow pattern of refrigerant R-290 in a horizontal evaporator are discussed. To simplify the analysis, the evaporator was divided into 10 segments. The void fraction was calculated based on the refrigerant flow quality and the flow pattern was determined on the basis of superficial gas and liquid velocity plotted in the flow pattern map. The calculation was carried on air conditioning machines with nominal capacities of 2.64 kW, 3.62 kW, and 5.28 kW using the evaporator pipe diameters of 3/8 in and 5/16 in. Generally, the lower evaporating temperature results in the higher void fraction, higher gas superficial velocity, and lower liquid superficial velocity. For all ranges of evaporator diameter and cooling capacity, annular flow is found to be the dominant flow pattern. The wavy flow is only found in the lower cooling capacity and larger evaporator diameter. Meanwhile, the slug flow occupies 16.7% to 25.8% of evaporator segment.

APA, Harvard, Vancouver, ISO, and other styles

18

Venkatachalam, Sivakumar, Akilamudhan Palaniappan, Senthilkumar Kandasamy, and Kannan Kandasamy. "Prediction of gas holdup in a combined loop air lift fluidized bed reactor using Newtonian and non-Newtonian liquids." Chemical Industry and Chemical Engineering Quarterly 17, no. 3 (2011): 375–83. http://dx.doi.org/10.2298/ciceq110401024v.

Full text

Abstract:

Many experiments have been conducted to study the hydrodynamic characteristics of column reactors and loop reactors. In this present work a novel combined loop airlift fluidized bed reactor was developed to study, the effect of superficial gas and liquid velocities, particle diameter, fluid properties on gas holdup by using Newtonian and non-Newtonian liquids. Compressed air was used as gas phase. Water, 5% n-butanol, various concentrations of glycerol (60 % and 80 %) were used as Newtonian liquids, different concentrations of Carboxy Methyl Cellulose (0.25 %, 0.6 % and 1.0 %) aqueous solutions were used as non-Newtonian liquids. Different sizes of Spheres, Bearl saddles and Raschig rings were used as solid phases. From the experimental results it was found that the increase in superficial gas velocity increases the gas holdup, but it decreases with increase in superficial liquid velocity and viscosity of liquids. Based on the experimental results a correlation was developed to predict the gas holdup for Newtonian and non-Newtonian liquids for a wide range of operating conditions at a homogeneous flow regime where the superficial gas velocity is approximately less than 5 cm/s.

APA, Harvard, Vancouver, ISO, and other styles

19

Huang, Yichuan, Hongye Zhu, Xingtuan Yang, Jiyuan Tu, and Shengyao Jiang. "Population balance modeling for air–water bubbly flow in a vertical U-bend." Journal of Computational Multiphase Flows 10, no. 4 (August 21, 2018): 170–77. http://dx.doi.org/10.1177/1757482x18791904.

Full text

Abstract:

Bubbly flow in U-bend is widely encountered in two-phase flow systems because of its compactness and high heat transfer coefficient. The modeling of phase distributions, velocity fields, and interfacial area concentration in the U-bend is crucial for the analysis of mass, momentum, and energy transportation processes in the equipment. However, this subject has not received enough attention yet. In this paper, the combination of population balance model and two-fluid model was used in the simulation of air–water bubbly flow in a U-bend with 24 mm inner diameter and 96 mm curvature. The homogeneous multiple size group model was used to solve the population balance equation and reconstruct the bubble size distribution function. The phase distribution at 0°, 90°, and 180° was predicted and the results showed that the superficial velocities of gas and liquid phase were the control parameters. Under higher gas superficial velocity, the buoyant force is dominant and makes the bubbles concentrate on the outer side of the tube wall; while under lower gas superficial velocity, the centrifugal force is dominant and makes the bubbles concentrate on the inner side of the tube wall. These results met well with the experimental results of Usui.

APA, Harvard, Vancouver, ISO, and other styles

20

Zainon, Mohd Zamri, Mohd Ardan Zubir, and Rahizar Ramli. "Transition of Bubbly to Slug Flow in a Short Vertical Channel of Gas-Liquid Two-Phase Flow." Advanced Materials Research 881-883 (January 2014): 721–25. http://dx.doi.org/10.4028/www.scientific.net/amr.881-883.721.

Full text

Abstract:

Transitions of bubbly to slug flow have been investigated for wide range of flow conditions via visualization technique. The effects of velocities of both phases were examined with variety of combinations and the experimentations were focused on the air-water flow with an industrial scale two-phase flow loop. The results show that the formations of slugs were easy with the increasing gas superficial velocity during a fixed liquid superficial velocity and were difficult when velocity of the liquid phase increases. These transitions were then evaluated using the ratio of velocities of both phases or called the slip ratio and from there a simple flow pattern map was constructed.

APA, Harvard, Vancouver, ISO, and other styles

21

Prasetyo, Ari, Setya Wijayanta, Indarto Indarto, and Deendarlianto Deendarlianto. "PENGARUH TEGANGAN PERMUKAAN PADA TEBAL FILM CAIRAN DAN KARAKTERISTIK GELOMBANG ANTARMUKA ALIRAN DUA FASE STRATIFIED HORIZONTAL." Jurnal Rekayasa Mesin 13, no. 3 (December 31, 2022): 805–17. http://dx.doi.org/10.21776/jrm.v13i3.1212.

Full text

Abstract:

This experimental study aims to examine the effect of the surface tension on the characteristics of unidirectional air-liquid interface waves on a horizontal pipe. The pipe used is an acrylic pipe with a diameter of 26 mm. To vary the surface tension, the working fluid consisted of 100% water and water mixed with 2% and 5% butanol. with surface tension (σ) values of 72, 58, and 42.5 mN/m, respectively. The wave characteristics studied in this research include the interface wave structure which is analyzed from visual observations and parameters by image processing. The superficial velocities of gas and liquid were varied in the range of 4-16 m/s and 0.02-0.1 m/s, respectively. Wave velocity and frequency were determined by using cross-correlation and power spectra density (PSD) from time-series data of liquid film thickness. Generally, velocity increases as the gas superficial velocity and surface tension decrease, the high gas superficial velocity the dominant frequency is high.

APA, Harvard, Vancouver, ISO, and other styles

22

Mohammadikharkeshi, Mobina, Ramin Dabirian, Ram S. Mohan, and Ovadia Shoham. "Experimental Study and Modeling of Slug Dissipation in a Horizontal Enlarged Impacting Tee-Junction." SPE Journal 25, no. 05 (June 1, 2020): 2508–20. http://dx.doi.org/10.2118/190131-pa.

Full text

Abstract:

Summary A novel experimental and theoretical study on slug dissipation in a horizontal enlarged impacting tee-junction (EIT) is carried out. Both flowing-slug injection and stationary-slug injection into the EIT are studied, and the effects of inlet slug length and liquid-phase fluid properties on the slug dissipation in the EIT are investigated. A total of 161 experimental data are acquired for air-water and air-oil flow. The flowing-slug data (with a horizontal inlet) show that the slug dissipation length increases with increasing mixture velocity, demonstrating a nonlinear trend with a steeper slope at lower mixture velocities. The effect of superficial gas velocity on the slug dissipation length is more pronounced compared with the effect of superficial liquid velocity. For stationary-slug injection into the EIT (with a 5° upward inclined inlet), the injected slug lengths vary between 40d to 100d (d is the inlet diameter). The data reveal that, when increasing the superficial gas velocity or the inlet slug size, the dissipation length in the EIT branches increases. For this case, the ratio of the slug dissipation length to the inlet slug length is higher for air-water compared with air-oil. A slug dissipation model is developed using the slug-tracking approach, which is based on the flow mechanisms of liquid shedding at the back of the slug and liquid drainage and penetration of bubble turning at the front of the slug. These phenomena result in different translational velocities at the back and the front of the slug, which result in the dissipation of the slug body. Evaluation of model predictions against the acquired experimental data shows an average absolute relative error of less than 11%.

APA, Harvard, Vancouver, ISO, and other styles

23

MUDDE, ROBERT F., and TAKAYUKI SAITO. "Hydrodynamical similarities between bubble column and bubbly pipe flow." Journal of Fluid Mechanics 437 (June 22, 2001): 203–28. http://dx.doi.org/10.1017/s0022112001004335.

Full text

Abstract:

The hydrodynamical similarities between the bubbly flow in a bubble column and in a pipe with vertical upward liquid flow are investigated. The system concerns air/water bubbly flow in a vertical cylinder of 14.9 cm inner diameter. Measurements of the radial distribution of the liquid velocity, gas fraction and the bubble velocity and size are performed using laser Doppler anemometry for the liquid velocity and a four-point optical fibre probe for the gas fraction, bubble velocity and size. The averaged gas fraction was 5.2% for the bubble column (with a superficial liquid velocity of zero) and 5.5% for the bubbly pipe flow at a superficial liquid velocity of 0.175 m s−1. From a hydrodynamical point of view, the two modes of operation are very similar. It is found that in many respects the bubbly pipe flow is the superposition of the flow in the bubble column mode and single-phase flow at the same superficial liquid velocity.The radial gas fraction profiles are the same and the velocity profiles differ only by a constant offset: the superficial liquid velocity. This means that the well-known large-scale liquid circulation (in a time-averaged sense) of the bubble column is also present in the bubbly pipe flow. For the turbulence intensities it is found that the bubbly pipe flow is like the superposition of the bubble column and the single-phase flow at the superficial liquid velocity of the pipe flow, the former being at least an order of magnitude higher than the latter. The large vortical structures that have been found in the bubble columns are also present in the bubbly pipe flow case, partly explaining the much higher ‘turbulence’ levels observed.

APA, Harvard, Vancouver, ISO, and other styles

24

Al-Hadhrami, Luai M., S. M. Shaahid, Lukman O. Tunde, and A. Al-Sarkhi. "Experimental Study on the Flow Regimes and Pressure Gradients of Air-Oil-Water Three-Phase Flow in Horizontal Pipes." Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/810527.

Full text

Abstract:

An experimental investigation has been carried out to study the flow regimes and pressure gradients of air-oil-water three-phase flows in 2.25 ID horizontal pipe at different flow conditions. The effects of water cuts, liquid and gas velocities on flow patterns and pressure gradients have been studied. The experiments have been conducted at 20°C using low viscosity Safrasol D80 oil, tap water and air. Superficial water and oil velocities were varied from 0.3 m/s to 3 m/s and air velocity varied from 0.29 m/s to 52.5 m/s to cover wide range of flow patterns. The experiments were performed for 10% to 90% water cuts. The flow patterns were observed and recorded using high speed video camera while the pressure drops were measured using pressure transducers and U-tube manometers. The flow patterns show strong dependence on water fraction, gas velocities, and liquid velocities. The observed flow patterns are stratified (smooth and wavy), elongated bubble, slug, dispersed bubble, and annular flow patterns. The pressure gradients have been found to increase with the increase in gas flow rates. Also, for a given superficial gas velocity, the pressure gradients increased with the increase in the superficial liquid velocity. The pressure gradient first increases and then decreases with increasing water cut. In general, phase inversion was observed with increase in the water cut. The experimental results have been compared with the existing unified Model and a good agreement has been noticed.

APA, Harvard, Vancouver, ISO, and other styles

25

Khanali, Majid, and Shahin Rafiee. "Investigation of Hydrodynamics, Kinetics, Energetic and Exergetic Aspects of Fluidized Bed Drying of Rough Rice." International Journal of Food Engineering 10, no. 1 (February 4, 2014): 39–50. http://dx.doi.org/10.1515/ijfe-2012-0116.

Full text

Abstract:

Abstract The hydrodynamics, kinetics as well as energy and exergy analyses of fluidized bed drying of rough rice under various experimental conditions were investigated. Drying experiments were conducted at drying air temperatures of 55, 60, and 70°C, superficial fluidization velocities of 2.3, 2.5, and 2.8 m/s, solid holdups of 0.66 and 1.32 kg, and rough rice initial moisture content of 0.25 d.b. Various popular drying models were used to fit the drying data. It was found that the fluidized bed hydrodynamics of the rough rice was uniform and stable. The drying rate was found to increase with increase in drying air temperature and superficial fluidization velocity, while decreased with increase in solid holdup. Statistical analyses showed that the Midilli et al. model was the best model in describing fluidized bed drying characteristics of the rough rice. The results showed that the values of energy efficiency were higher than the corresponding values of exergy efficiency during the entire drying process. Furthermore, at initial stage of drying, the energy and exergy efficiencies were higher than those at the end of drying. It was also found that both the energy and the exergy efficiencies increased with increasing drying air temperature and solid holdup, whereas decreased with the increase in superficial fluidization velocity.

APA, Harvard, Vancouver, ISO, and other styles

26

Kim, S., S. S. Paranjape, M. Ishii, and J. Kelly. "Interfacial Structures and Regime Transition in Co-Current Downward Bubbly Flow." Journal of Fluids Engineering 126, no. 4 (July 1, 2004): 528–38. http://dx.doi.org/10.1115/1.1777229.

Full text

Abstract:

The vertical co-current downward air-water two-phase flow was studied under adiabatic condition in round tube test sections of 25.4-mm and 50.8-mm ID. In flow regime identification, a new approach was employed to minimize the subjective judgment. It was found that the flow regimes in the co-current downward flow strongly depend on the channel size. In addition, various local two-phase flow parameters were acquired by the multi-sensor miniaturized conductivity probe in bubbly flow. Furthermore, the area-averaged data acquired by the impedance void meter were analyzed using the drift flux model. Three different distributions parameters were developed for different ranges of non-dimensional superficial velocity, defined by the ration of total superficial velocity to the drift velocity.

APA, Harvard, Vancouver, ISO, and other styles

27

Shukrullah, Javed, Naz, Khan, Alkanhal, and Anwar. "PIV and Statistical Analysis of a Swirling Bed Process Carried out Using a Hybrid Model of Axial Blade Distributor." Processes 7, no. 10 (October 3, 2019): 697. http://dx.doi.org/10.3390/pr7100697.

Full text

Abstract:

: An air distributor is a major component of industrial fluidized beds and its design significantly affects the quality of fluidization. In this study, a hybrid design of an annular distributor was tested for swirling fluidized beds (SFBs). Using this distributor design, a bed was operated in its uniform swirling regime of operation. A high-speed imaging method was used to capture images of the fluidized bed of particles. These images were processed using a binary cross-correlation technique and analyzed through particle image velocimetry (PIV) software. The velocity vector fields and corresponding velocity magnitudes at different locations in the bed were obtained for different bed weights, blade inclination angles, and superficial air velocities (SAVs). The Response Surface Analysis program was used to predict the bed velocity statistically. The statistical confidence interval for the bed velocity ranged from 0.49485 to 0.49998. The statistical fit and experimental values of the bed velocities were 0.49741 and 0.538 m/s, respectively. Almost identical bed weights and superficial velocities were inferred through experimental and statistical analyses; however, a small difference of 6.4° was noticed in the blade inclination angles.

APA, Harvard, Vancouver, ISO, and other styles

28

Stamenkovic, Ivica, Olivera Stamenkovic, Ivana Bankovic-Ilic, Miodrag Lazic, Vlada Veljkovic, and Dejan Skala. "The gas holdup in a multiphase reciprocating plate column filled with carboxymethylcellulose solutions." Journal of the Serbian Chemical Society 70, no. 12 (2005): 1533–44. http://dx.doi.org/10.2298/jsc0512533s.

Full text

Abstract:

Gas holdup was investigated in a gas-liquid and gas-liquid-solid reciprocating plate column (RPC) under various operation conditions. Aqueous carboxymethyl cellulose (sodium salt, CMC) solutions were used as the liquid phase, the solid phase was spheres placed into interplate spaces, and the gas phase was air. The gas holdup in the RPC was influenced by: the vibration intensity, i.e., the power consumption, the superficial gas velocity, the solids content and the rheological properties of the liquid phase. The gas holdup increased with increasing vibration intensity and superficial gas velocity in both the two- and three-phase system. With increasing concentration of the CMC PP 50 solution (Newtonian fluid), the gas holdup decreased, because the coalescence of the bubbles was favored by the higher liquid viscosity. In the case of the CMC PP 200 solutions (non-Newtonian liquids), the gas holdup depends on the combined influence of the rheological properties of the liquid phase, the vibration intensity and the superficial gas velocity. The gas holdup in the three-phase systems was greater than that in the two-phase ones under the same operating conditions. Increasing the solids content has little influence on the gas holdup. The gas holdup was correlated with the power consumption (either the time-averaged or total power consumption) and the superficial gas velocity.

APA, Harvard, Vancouver, ISO, and other styles

29

Arabi, Abderraouf, Yacine Salhi, Amina Bouderbal, Youcef Zenati, El-Khider Si-Ahmed, and Jack Legrand. "Onset of intermittent flow: Visualization of flow structures." Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 76 (2021): 27. http://dx.doi.org/10.2516/ogst/2021009.

Full text

Abstract:

The transition from stratified to intermittent air-water two-phase flow was investigated experimentally, by flow visualization and pressure drop signals analyses, in a 30 mm ID pipe. The intermittent flow’s onset was found to be mainly dependent on the liquid superficial velocity and the pipe diameter. Plug flow, Less Aerated Slug (LAS) or Highly Aerated Slug (HAS) flows could be obtained on the gas superficial velocity grounds. The available models, compared to experiments, could not predict adequately the intermittent flow onset. The appearance of liquid slugs was revealed by peaks in the pressure drop signal. Furthermore, it was shown that the available slug frequency correlations were not valid in the zone of the onset of intermittent flow.

APA, Harvard, Vancouver, ISO, and other styles

30

Messilem, Abdelkader, Abdelwahid Azzi, Ammar Zeghloul, Faiza Saidj, Hiba Bouyahiaoui, and Al-Sarkhi Abdelsalam. "Single- and two-phase pressure drop through vertical Venturis." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 12 (February 11, 2020): 2349–59. http://dx.doi.org/10.1177/0954406220906424.

Full text

Abstract:

An experimental investigation of the pressure drops measurements in a Venturi placed in a vertical pipe is achieved. Venturis with diameter ratios equal to 0.4, 0.55, and 0.75 were employed. Differential pressure transducers were used to measure the pressure drop between the Venturi inlet and the throat sections. The void fraction was measured upstream the Venturi using a conductance probe technique. Air and water superficial velocities ranges were chosen to cover single-phase flow and bubbly, slug, and churn flow regimes. The single-phase pressure drop increases with the liquid superficial velocity. The Venturi pressure drop coefficient increases with decreasing the Venturi area ratio. The discharge coefficient increases slightly with this ratio and approaches a value of unity at high Reynolds number. The two-phase flow pressure drop and the multiplier coefficient increase with the gas superficial velocity and with decreasing the area ratio. Dimensionless pressure drop decreases with increasing the liquid to gas superficial velocity ratio and approaches an asymptotic value at high ratio (greater than 10). This value matches the single-phase flow dimensionless pressure drop value at high Reynolds number. The Venturi with area ratio equal to 0.55 was shown to correlate well the two-phase multiplier and the liquid holdup.

APA, Harvard, Vancouver, ISO, and other styles

31

Awwad, A., R. C. Xin, Z. F. Dong, M. A. Ebadian, and H. M. Soliman. "Flow Patterns and Pressure Drop in Air/Water Two-Phase Flow in Horizontal Helicoidal Pipes." Journal of Fluids Engineering 117, no. 4 (December 1, 1995): 720–26. http://dx.doi.org/10.1115/1.2817328.

Full text

Abstract:

An experimental investigation is conducted for air/water two-phase flow in horizontal helicoidal pipes. The helicoidal pipes are constructed of 25.4 mm I.D. Tygon tubing wrapped around cylindrical concrete forms with outside diameters of 62 cm and 124 cm. The helix angles of the helicoidal pipes vary from 1 to 20 deg. The experiments are performed for superficial water velocity in a range of UL = 0.008 ~ 2.2 m/s and for superficial air velocity in a range of UG = 0.2 ~ 50 m/s. The flow patterns are discerned and recorded photographically. The pressure drop of the air/water two-phase flow in the coils is measured and the Lockhart-Martinelli approach is used to analyze the data. The results are presented in the form of frictional pressure drop multipliers versus the Lockhart-Martinelli parameter. It was found that the flow patterns differ greatly from those of the straight pipe, and that the frictional pressure drop multipliers depend on both the Lockhart-Martinelli parameter and the flow rates. The correlation of the frictional pressure drop has been provided based on the current data. Furthermore, it was also found that the helix angle of the helicoidal pipe had almost no effect on the air/water two-phase flow pressure drop in the present experimental ranges.

APA, Harvard, Vancouver, ISO, and other styles

32

Jokić, Aleksandar, Ivana Pajčin, Nataša Lukić, Vanja Vlajkov, Arpad Kiralj, Selena Dmitrović, and Jovana Grahovac. "Modeling and Optimization of Gas Sparging-Assisted Bacterial Cultivation Broth Microfiltration by Response Surface Methodology and Genetic Algorithm." Membranes 11, no. 9 (September 1, 2021): 681. http://dx.doi.org/10.3390/membranes11090681.

Full text

Abstract:

Production of highly efficient biomass-based microbial biopesticides significantly depends on downstream processing in terms of obtaining as high concentration of viable cells as possible. Microfiltration is one of the recommended operations for microbial biomass separation, but its main limitation is permeate flux decrease due to the membrane fouling. The effect of air sparging as a hydrodynamic technique for improvement of permeate flux during microfiltration of Bacillus velezensis cultivation broth was investigated. Modeling of the microfiltration was performed using the response surface methodology, while desirability function approach and genetic algorithm were applied for optimization, i.e., maximization of permeate flux and minimization of specific energy consumption. The results have revealed antagonistic relationship between the investigated dependent variables. The optimized values of superficial feed velocity and transmembrane pressure were close to the mean values of the investigated value ranges (0.68 bar and 0.96 m/s, respectively), while the optimized value of superficial air velocity had a more narrow distribution around 0.25 m/s. The results of this study have revealed a significant improvement of microfiltration performance by applying air sparging, thus this flux improvement method should be further investigated in downstream processing of different bacterial cultivation broths.

APA, Harvard, Vancouver, ISO, and other styles

33

Wibawanto, Latif Ngudi, Budi Santoso, and Wibawa Endra Juwana. "Karakteristik aliran dua fase pada saluran ekspansi tiba-tiba." Jurnal Teknik Mesin Indonesia 11, no. 1 (March 5, 2018): 7. http://dx.doi.org/10.36289/jtmi.v11i1.44.

Full text

Abstract:

This research was conducted to find out the flow characteristic of two phases through the channel with sudden expansion in the form of change of flow pattern and pressure recovery. The test was carried out with variation of superficial velocity of water 0.2-1.3 m / s and superficial air velocity of 0.2-1.9 m / s resulting in pattern of three flow patterns ie bubble, plug, and slug. The expansion channel resulted in some changes to the flow pattern that originally plugs in the upstream channel into bubble in the downstream channel and the slug becomes plug. Pressure recovery experimental results compared with the homogeneous model flow equation and Wadle correlation, both correlations have predictions with standard deviation values of 0.32 and 0.43.

APA, Harvard, Vancouver, ISO, and other styles

34

Yang, Zhang, Liang, and Lu. "Research on an Artificial Lateral Line System Based on a Bionic Hair Sensor with Resonant Readout." Micromachines 10, no. 11 (October 29, 2019): 736. http://dx.doi.org/10.3390/mi10110736.

Full text

Abstract:

Inspired by the lateral line system of fish, an artificial lateral line system based on bionic hair sensor with resonant readout is presented in this paper. An artificial lateral line system, which possesses great application potential in the field of gas flow visualization, includes two different sensors: a superficial neuromast and a canal neuromast flow velocity sensor, which are used to measure the constant and oscillatory air flow velocity, respectively. The sensitive mechanism of two artificial lateral line sensors is analyzed, and a finite element simulation is implemented to verify the structural design. Then the control circuit of the artificial lateral line system is designed, employing a demodulation algorithm of oscillatory signal based on the least mean square error algorithm, which is used to calculate the oscillatory air flow velocity. Finally, the experiments are implemented to assess the performance of the two artificial lateral line systems. The experimental results show that the artificial lateral line system, which can be used to measure the constant and oscillatory air flow velocity, has a minimum threshold of 0.785 mm/s in the measurement of oscillatory air flow velocity. Moreover, the artificial canal neuromast lateral line system can filter out low-frequency disturbance and has good sensitivity for high-frequency flow velocity.

APA, Harvard, Vancouver, ISO, and other styles

35

El-Alej, Mohamed, David Mba, Ting Hu Yan, and Shuib Husin. "Investigation on Sand Particle Impingement on Steel Pipe in Two Phase Flow Using Acoustic Emission Technology." Applied Mechanics and Materials 315 (April 2013): 540–44. http://dx.doi.org/10.4028/www.scientific.net/amm.315.540.

Full text

Abstract:

This paper presents an experimental investigation that employed the acoustic emission (AE) technology to monitor sand transportation in two-phase flow. This investigation was undertaken on two phase (air-sand) flow in a horizontal pipe for varying Superficial Gas Velocities (VSG). The objective of this research programme is to develop a simple, non-invasive technique for monitoring of sand particle concentration levels in multi-phase flow conditions. The experimental findings show that AE absolute energy can be correlated with the size of sand, number of sand particles and Superficial Gas Velocity (VSG).

APA, Harvard, Vancouver, ISO, and other styles

36

Han, Lu, Premkumar Kamalanathan, and Muthanna H. Al-Dahhan. "Gas–liquid mass transfer using advanced optical probe in a mimicked FT slurry bubble column." International Journal of Chemical Reactor Engineering 19, no. 1 (December 25, 2020): 31–42. http://dx.doi.org/10.1515/ijcre-2020-0143.

Full text

Abstract:

Abstract Gas-liquid volumetric liquid-phase mass transfer coefficient (k L a) was studied in a slurry bubble column at the conditions mimicking Fischer–Tropsch synthesis. To avoid the hydrodynamic disturbances due to the gas switching, oxygen enriched air dynamic absorption method was used. Influence of reactor models (CSTR, ADM and RCFD) on the volumetric mass transfer coefficient was investigated. Effect of operating pressure, superficial gas velocity and solids loading were investigated. From the reactor models investigated, it is recommended to use ADM model for k L a study. If the CSTR model is used, applicability of the model should be checked. With increase in the superficial gas velocity and operating pressure, volumetric liquid-phase mass transfer coefficient increases, while it decreases with the solids loading corroborating with the literature.

APA, Harvard, Vancouver, ISO, and other styles

37

Balchugov, Alexey, and Artem Badenikov. "Experimental Observation of a Regression Dependence for Hydrodynamic Performance of the Regular Packing." MATEC Web of Conferences 346 (2021): 03012. http://dx.doi.org/10.1051/matecconf/202134603012.

Full text

Abstract:

The investigational studies of regression dependence of the new efficient regular packing bed’s flow friction on gas velocity and liquid spray rate has been carried out. The tests were made by the procedure of a complete two-factor experiment. On account of experiment design matrix, there are four tests to be made to determine the regression dependence. It is found that the packing bed’s flow friction builds up along with increase of superficial gas velocity and liquid spray rate. The regression dependence that puts packing bed’s flow friction in touch with superficial gas velocity and liquid spray rate is procured. The specific dependence is valid for air velocity 1.21-3.12 m/sec and liquid spray rate 0.0080-0.0304 m3/(m2 sec). The conclusion on significance of regression dependencies has been made in terms of Student’s t-test. The sufficiency of regression equation has been inspected via the Fisher’s criterion. The resulting regression equation can be utilized in the design and engineering process of absorbers with the shock-spray packing.

APA, Harvard, Vancouver, ISO, and other styles

38

Baca, H., D. E. Nikitopoulos, J. R. Smith, and A. T. Bourgoyne. "Counter-Current and Co-Current Gas Kicks in “Horizontal” Wells: Non-Newtonian Rheology Effects." Journal of Energy Resources Technology 125, no. 1 (March 1, 2003): 51–60. http://dx.doi.org/10.1115/1.1555659.

Full text

Abstract:

Results from experiments conducted in downward liquid-gas flows in inclined, eccentric annular pipes, with water-air and water-polymer-air mixtures as the working fluids, are presented. The gas was injected near the middle of the test-section length. This flow is directly relevant to what is found in down-grade portions of “horizontal” wells. Flow maps, in terms of liquid and gas superficial velocities, indicating the transitions between counter-current and co-current gas flows have been determined experimentally for four dip angles. The counter-current gas flow observed was always in the slug regime while the co-current one appeared as stratified. Counter-current flow fraction and void fraction measurements were carried out at various liquid superficial velocities and gas-injection rates and correlated to visual observations through a full-scale transparent test section. Results indicate that increase of the liquid yield point favors the development of counter current flow which is shown to occur at representative liquid superficial velocities and gas injection rates. Thus, counter-current flow can be easily generated at small downward dip angles, within the practical range of liquid superficial velocity for drilling operations, especially at low gas-injection rates.

APA, Harvard, Vancouver, ISO, and other styles

39

Jayadi, Farid, Sudarja Sudarja, and Eli Komolosari. "Karakteristik Pola Aliran Air-Udara, Campuran Air+Gliserin (G20)-Udara, dan Campuran Akuades+Butanol 4%-Udara Pada Pipa Horizontal Berukuran Mini." Jurnal Mekanova : Mekanikal, Inovasi dan Teknologi 8, no. 2 (November 26, 2022): 332. http://dx.doi.org/10.35308/jmkn.v8i2.6470.

Full text

Abstract:

This study aims to obtain information about the flow characteristics of Water-Air Flow, Mixture of Glycerin+Water(G20)-Air, and Mixture of Aquadest+Butanol 4%-Air. The two-phase flow characteristics in mini-sized pipes have significant differences with the two-phase flow characteristics in conventional pipes, so it will affect fluid distribution processes involving two-phase flow such as heat transfer processes. Therefore, it is necessary to conduct further studies on the two-phase flow pattern in mini-sized pipes. This research was conducted in a test section in the form of a glass pipe with a diameter of 1.6 mm in a horizontal position. The liquid fluid used is water which has a surface tension (σ) of 71 mN/m, a mixture of glycerin+water (G20) has a surface tension (σ) of 62.5 mN/m, and a mixture of distilled water+butanol 4% has a surface tension (σ) of 36.50 mN/m. Superficial velocity of gas (JG)=0.033–4.935 m/s, and superficial velocity of liquid (JL)=0.025–66.3 m/s. The results showed that stratified flow was not observed in the mini channel as can be found in conventional pipes. The detected flow patterns are: bubbly, slug, slug-annular, churn, and annular. The results of flow pattern maps compared with flow pattern maps from Triplett et al (1999a), Chung and Kawaji (2004) and Sudarja et al (2014), and Aqli et al (2015) show that the higher the viscosity, the higher the annular churn-slug flow transition line will be. decreases while the annular – slug annular transition line tends to be more sloping.

APA, Harvard, Vancouver, ISO, and other styles

40

Setyawan, Andriyanto, Indarto, Deendarlianto, and Prasetyo. "Effects of Surface Tension on the Liquid Holdup and Wave Characteristics in Horizontal Annular Two-Phase Flow." Applied Mechanics and Materials 771 (July 2015): 248–51. http://dx.doi.org/10.4028/www.scientific.net/amm.771.248.

Full text

Abstract:

The wave characteristics of horizontal annular two-phase flow in 16 mm diameter pipe were experimentally investigated using flush-mounted constant electric current method (CECM) sensors and visual observations. To examine the effect of surface tension on the wave velocity and frequency, air and three kinds of liquids with different surface tension were used, i.e., water, 2%-butanol solution, and 5%-butanol solution. The gas and liquid superficial velocities were varied from 12 to 40 m/s and 0.05 to 0.2 m/s, respectively. The liquid holdup was measured directly using CECM, while the wave velocity and frequency were determined using cross correlation and power spectral density functions of liquid holdup signals. Generally, combination of air and liquid with the highest surface tension gives the highest liquid holdup and wave frequency. Simple correlations for wave velocity and wave frequency were also developed.

APA, Harvard, Vancouver, ISO, and other styles

41

Hua, Ze Jia, Na Huang, and Ju Gao. "Characteristics Research of Gas-Liquid Two Phase Flow Based on the VOF Model in T Tube." Applied Mechanics and Materials 448-453 (October 2013): 3073–77. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.3073.

Full text

Abstract:

Using numerical simulation method, under the adiabatic condition, this paper simulates the of the upstream gas liquid two phase flow in main tube of hydraulic diameter 1 mm T tube. Superficial gas velocity within 0.01~30m/s and fluid velocity within 0.01~5m/s, under simulated by two kinds of gas volume fraction, air-water flow diagram and the flow pattern transition boundary have been got from the simulation. By comparing the simulation results, it shows that under the same environment, small channel volume fraction of gas has important influence on convection type transition boundaries.

APA, Harvard, Vancouver, ISO, and other styles

42

Olive, Nicolas R., Hong-Quan Zhang, Qian Wang, Clifford L. Redus, and James P. Brill. "Experimental Study of Low Liquid Loading Gas-Liquid Flow in Near-Horizontal Pipes." Journal of Energy Resources Technology 125, no. 4 (November 18, 2003): 294–98. http://dx.doi.org/10.1115/1.1625394.

Full text

Abstract:

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.)

APA, Harvard, Vancouver, ISO, and other styles

43

Hosseinzadeh, Mostafa, Mohammad Reza Mehrnia, and Navid Mostoufi. "Experimental Study and Modeling of Fouling in Immersed Membrane Bioreactor Operating in Constant Pressure Filtration." Mathematical Problems in Engineering 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/456143.

Full text

Abstract:

A new mathematical model is proposed based on filtration mechanisms for the prediction of fouling in airlift immersed membrane bioreactors (iMBRs). The cake formation on the membrane surface through constant pressure filtration process in the iMBR was explained by a proposed cake filtration mechanism which assumes that no particle enters the pores when forming the cake layer on the membrane surface. The cake porosity reduction due to diffusion of particles was described by an intermediate blocking mechanism. Experimental study of fouling was also performed in a lab-scale airlift flat-sheet iMBR operating at constant vacuum. The mixed liquor suspended solid (MLSS) concentration was changed within the range of 5000 to 15000 mg/L, while the superficial air velocity was varied between 32 and 128 m3/m2/h. The presented model includes two parameters, that is, ultimate filtration resistance and initial rate of cake formation. The effect of the MLSS concentration and superficial air velocity on the parameters of the proposed model was studied. The results obtained from the model demonstrated that the ultimate filtration resistance and the initial rate of cake formation are more sensitive to the aeration rate at lower superficial velocities. It was also shown that the ultimate filtration resistance has a linear relation with MLSS concentration. A good agreement exists between the results of the model and the experimental data. The proposed model also showed a better compatibility with the experimental data compared to other fouling models available in the literature.

APA, Harvard, Vancouver, ISO, and other styles

44

Vasic, Ljubisa, Ivana Bankovic-Ilic, Miodrag Lazic, Vlada Veljkovic, and Dejan Skala. "Gas-holdup in a 16.6 cm I.D. reciprocating plate column." Chemical Industry 59, no. 9-10 (2005): 263–66. http://dx.doi.org/10.2298/hemind0510263v.

Full text

Abstract:

The effects of operation conditions (the vibration intensity and gas flow rate) on the gas holdup in a 16.6 cm i.d. two-phase reciprocating plate column (RPC) were studied. Distilled water and aqueous solutions of carboxymethyl-cellulose of different concentration were used as the liquid phase and air as the gas phase in this investigation. The gas holdup was measured after the gas flow and the reciprocating action had been stopped. An empirical correlation which correlates the gas holdup with the specific power consumption and the superficial gas velocity showed that the aeration intensity had a greater influence on the gas holdup than the intensity of agitation. Because the gas holdup was approximately the same in RPC's of different diameters, an equation relating the gas holdup with the specific power consumption and the superficial gas velocity was derived. The correlation could be used in the scaling up of reciprocating plate columns.

APA, Harvard, Vancouver, ISO, and other styles

45

Halim, L. A., M. F. Basrawi, S. N. Faizal, A. S. M. Yudin, and T. M. Yusof. "Effect of superficial air velocity on the fluidized bed drying performance of stingless bee pot-pollen." IOP Conference Series: Materials Science and Engineering 863 (June 13, 2020): 012041. http://dx.doi.org/10.1088/1757-899x/863/1/012041.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Léonard, A., S. Blacher, P. Marchot, J. P. Pirard, and M. Crine. "Convective Drying of Wastewater Sludges: Influence of Air Temperature, Superficial Velocity, and Humidity on the Kinetics." Drying Technology 23, no. 8 (August 2005): 1667–79. http://dx.doi.org/10.1081/drt-200065082.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Tavares, C. "The effect of air superficial velocity on biofilm accumulation in a three-phase fluidized-bed reactor." Water Research 29, no. 10 (October 1995): 2293–98. http://dx.doi.org/10.1016/0043-1354(95)00043-k.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Thatchapol Chungcharoen, Warunee Limmun, and Sansanee Sansiribhan. "Effects of Coffee Form and Distributor Hole Angle on The Fluidization Behavior and Specific Energy Consumption in The Fluidized Bed Machine." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 84, no. 2 (July 25, 2021): 152–58. http://dx.doi.org/10.37934/arfmts.84.2.152158.

Full text

Abstract:

The fluidized bed technique was applied to use with the Robusta coffee in this research. fluidization behavior and specific energy consumption were investigated under various coffee forms and distributor hole angles. Moreover, the minimum fluidization velocity (Vmf) was also determined. Experiments are carried out in a sample bed height of 5 cm with ambience air. In this study, two coffee forms (Ripe coffee cherries; RCC and parchment coffee; PC) and three distributor hole angles (45º, 60º and 90º) are examined. The experimental result shown that the fluidization behavior is influenced by coffee form and distributor hole angle. The RCC and distributor hole angle of 60º provided the low pressure drop throughout the superficial air velocity. The low values of Vmf and SEC were also achieved in the RCC and distributor hole angle of 60º.

APA, Harvard, Vancouver, ISO, and other styles

49

Hayder Abd Al-kaream Muhsin. "EXPERIMENTAL STUDY OF LIQUID DISPERSION IN BUBBLE COLUMN." Diyala Journal of Engineering Sciences 1, no. 1 (September 1, 2008): 56–85. http://dx.doi.org/10.24237/djes.2008.01105.

Full text

Abstract:

The main object of this study is to investigate the influence of column diameter and superficial gas velocity on liquid phase dispersion coefficients (axial and radial dispersion coefficients), mixing times, gas holdup, and bubble dynamics (bubble diameter and rise velocity). The liquid phase dispersion, gas holdup, and bubble dynamics (Db and Vb0) were measured for the air-water system in bubble columns of two different diameters,15 and 30 cm. The superficial gas velocity, Ug, was varied in the range 1-10 cm/s, spanning both the homogeneous and heterogeneous flow regimes. The height of liquid in the column was kept constant at 130 cm for the two column. Axial and radial dispersion coefficients and mixing times were measured at various axial and radial locations inside the columns (Z = 25, 75, 125 cm and r/R = 0, 0.45, 0.85), bubble dynamics were measured at three axial location (Z=25, 75, 125 cm). From the experimental data it was found that, the value of the radial dispersion coefficient (Dr,L) and axial dispersion coefficient (Dax,L), gas holdup, bubble diameter and bubble rise velocity, increase with increasing superficial gas velocity. The results emphasise the significant influence of the column diameter on the hydrodynamics. Gas holdup showed a decrease with increasing column diameter, while the radial dispersion coefficient (Dr,L), axial dispersion coefficient (Dax,L), bubble diameter and bubble rise velocity increased with increasing column diameter. A statistical analysis was performed to get a general correlations for the axial liquid dispersion coefficient as a function of the mixing time and dispersion height (Hd), this correlations are: Dax,L=0.15 H2d /θ0.3 for 30 cm column diameter and Dax,L=0.11 H2d /θ0.3 for 15 cm column diameter.

APA, Harvard, Vancouver, ISO, and other styles

50

Abdulrazzaq, Burhan Sadeq. "Gas Holdup and Liquid-Phase Dispersion in Packed Bubble Columns." Tikrit Journal of Engineering Sciences 18, no. 3 (September 30, 2011): 13–22. http://dx.doi.org/10.25130/tjes.18.3.02.

Full text

Abstract:

The gas holdup and liquid phase axial dispersion coefficient are measured in two semi batch packed bubble columns, 10 and 15 cm diameter for an air–water system, at atmospheric conditions. The experiments were carried out using a transient method (the tracer response method). The dispersion coefficient was obtained by adjusting the experimental profiles of tracer concentration with the predictions of the model. Experiment results of packed bubble column, shows a considerable reduction of the back mixing. The investigations have been carried out using RTD measurements and the back mixing is usually characterized by the axial dispersion coefficient obtained from the one-dimensional axial dispersion model. Also, a decrease in superficial gas velocity reduces the liquid back mixing. It is observed that the liquid circulation comprises an upward flow in the column core and a downward flow along the wall. It also seen that the transition from the bubbly flow to the pulsation flow regime occurred at 5-6 cm/s superficial gas velocity.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Superficial air velocity'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles