scholarly journals Experimental Investigation of the Interaction between Rising Bubbles and Swirling Water Flow

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Tomomi Uchiyama ◽  
Shunsuke Sasaki
Keyword(s):  
Experimental Investigation ◽  
Water Flow ◽  
Flow Rate ◽  
Swirling Flow ◽  
Vertical Axis ◽  
Central Axis ◽  
Bubble Flow ◽  
Air Bubbles ◽  
Water Tank ◽  
Bubble Plume

This study experimentally investigates the interaction between rising bubbles and swirling water flow imposed around the central (vertical) axis of a bubble plume in a cylindrical water tank. Small air bubbles are successively released from the bottom of the tank to generate a bubble plume, and a stirring disc at the bottom of the tank is rotated to impose a swirling water flow around the central axis of the bubble plume. The bubbles disperse further with the increasing rotational speedωof the stirring disc. Some bubbles shift toward the central axis of the swirling flow whenωis high. The nondimensional swirling velocity of water reduces with increasing bubble flow rate whenωis lower than a certain value. However, it is less affected by the bubbles whenωis higher. The precessional amplitude for the upper end of the vortex core increases due to the presence of the bubbles. With increasingω, the nondimensional precessional velocity decreases, and the bubble effect also reduces.

Micro-scale simulation of bubble-water flow in coal seams by the lattice Boltzmann method

2016 ◽  
Vol 56 (2) ◽  
pp. 608
Author(s):  
Jie Yi ◽  
Huilin Xing ◽  
Tianwei Sun ◽  
Victor Rudolph
Keyword(s):  
Coal Seam ◽  
Water Flow ◽  
Flow Rate ◽  
Bubble Size ◽  
Lattice Boltzmann ◽  
Water Flow Rate ◽  
Bubble Flow ◽  
Coal Seam Gas ◽  
Two Phase ◽  
Flow Process

The production of coal seam gas initially requires pumping and removing significant amounts of water to sufficiently reduce the hydrostatic pressure in the subsurface, so that methane can desorb from the matrix and diffuse into the cleat systems; majority of the methane molecules gather into nucleation or bubbles. During the depression, the flow pattern of gas in cleats changes from bubble flow to slug flow, and finally forms circular flow. The significance of the bubble flow process—during which the liquid phase is continuous while the gas phase exists as small bubbles randomly distributed within the liquid—has not been emphasised because of its complexity. In this study, a free energy based two-phase lattice Boltzmann model is used to simulate the gas bubble/water flow behaviour in micro-cleats of a coal seam gas reservoir. The model was validated by comparison with analytical results based on dimensionless numbers, and good agreement was found in general. The influences of bubble shape, bubble size, and coal surface wettability on gas water two-phase flow in micro-cleats are discussed. The simulation results indicate that the bubble size and wettability of gas have significant impacts on the flow capacity of both gas and water. A decrease of the water flow rate is observed when large bubbles occur, and the gas flow rate decreases when the gas wettability becomes stronger. The bubble flow process significantly influences the drainage of water and the further gas production.

scholarly journals Experimental Analysis of SMART Scrubbing System with the Principle of Dynamic Precipitation

2018 ◽  
Vol 7 (4.35) ◽  
pp. 317
Author(s):  
Nirvenesh Ravindran ◽  
Hasril Hasini
Keyword(s):  
Experimental Investigation ◽  
Water Flow ◽  
Flow Rate ◽  
Experimental Analysis ◽  
Dust Concentration ◽  
Processing Plant ◽  
Dynamic Precipitation ◽  
Flow Rates ◽  
Model Experiments ◽  
Process Line

This paper presents an experimental investigation of a SMART scrubbing system in sugar processing plant. The objectives are to address the problem and develop new technique to increase the efficiency and eliminate sugar sludge production downstream of process line. The SMART scrubbing effect of water with the principal of dynamic precipitation was conducted on-site with calculated flow rate, which simulates the SMART scrubbing system. The on-site and scaled-down model experiments measure the upstream and downstream dust concentration and processes the flow rate of water required to counter the dust concentration based on the feedback flow. The investigation was conducted with a steady airflow of 6 m3/s with variation of water flow rates. The result of the on-site studies shows an excellent increase in average and maximum efficiencies of 98.77% and 99.3% respectively.

Optimization of oxygen transfer in clean water by fine bubble diffused air system and separate mixing in aeration ditches

1998 ◽  
Vol 38 (3) ◽  
pp. 35-42 ◽  
Author(s):  
G. Déronzier ◽  
Ph. Duchène ◽  
A. Héduit
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Oxygen Transfer ◽  
Contact Time ◽  
Air Flow ◽  
Interfacial Area ◽  
Design Parameters ◽  
Air Bubbles ◽  
Air Flow Rate ◽  
Fine Bubble

The influence of design parameters on the transfer of oxygen was studied in different ring ditches equipped with fine bubble membrane air diffusers and separate mixing. The results produced evidence that the oxygen transfer efficiency (OTE) decreases when the air flow rate per diffuser increases. OTE increases asymptotically with the horizontal water flow (50% for velocity up to 0.5 m/sec). It increases also when the diffuser modules are brought closer together. Theoretical analysis enabled ranking of the impact of the design parameters on which the oxygen transfer is dependent, namely the interfacial area (a) and the oxygen transfer coefficient (Kl). The increase in the air flow rate per diffuser essentially reduces the interfacial area by an increase in the diameter of the initial air bubbles and by a reduction of the contact time due to an acceleration of the “spiral flows” (vertical rotation of water flow). The horizontal rotation of water increases the interfacial area most probably by decreasing the diameter of the initial air bubbles and by a lengthening of the contact time resulting from a reduction in the large spiral flows. Bringing the diffuser modules closer together makes longer the contact time by a reduction in the large spiral flows.

scholarly journals Measurements of Nozzle Valve Flow Characteristicsin a Handy Shower Set

2021 ◽  
Vol 16 ◽  
pp. 1-7
Author(s):  
Wojciech Wolak ◽  
Krzysztof Dubaj ◽  
Artur Bartosik
Keyword(s):  
Hydrostatic Pressure ◽  
Water Flow ◽  
Flow Rate ◽  
Water Flow Rate ◽  
Volumetric Flow Rate ◽  
Personal Hygiene ◽  
Water Tank ◽  
Water Shortages ◽  
Pressure Drops ◽  
Valve Opening

The paper deals with nozzle valve characteristics used in modern portable device, named handy shower, dedicated for personal hygiene. Such device significantly reduces water consumption and can be easily and quickly changed into a shower, sink or bidet. Importance of such device continuously rises as some regions and cities face water shortages. The aim of the paper is to measure and analyse characteristics of nozzle valves in portable handy shower for different hight of hydrostatic pressure, different number of holes in the nozzle and different level of valve opening. Experiments required measurements of volumetric flow rate and pressure drops. The pressure drops on the nozzle valve were measured using differential pressure transducer with accuracy of 1 Pa, while the water flow rate at the outlet of the nozzle was measured using the time-volume method with accuracy for volume and time 1ml and 0.1s, respectively. Experiments confirmed substantial influence of hight of hydrostatic pressure, number of holes in the nozzle, and the level of valve opening on outlet water flow rate from the device. It is demonstrated that for chosen height of hydrostatic pressure and for filled water tank it is possible to calculate duration of the use of handy shower for specific hygiene purpose by choosing appropriate level of valve opening and the right nozzle valve with a certain number of holes. Authors discussed possible reason that some of measured points are scattered at low level of valve opening. Results of experience were presented as graphs and conclusions.

The turbulent kinetic energy budget in a bubble plume

2019 ◽  
Vol 865 ◽  
pp. 993-1041 ◽  
Author(s):  
Chris C. K. Lai ◽  
Scott A. Socolofsky
Keyword(s):  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Liquid Velocity ◽  
Temporal Frequency ◽  
Asymptotic State ◽  
Air Bubbles ◽  
Water Tank ◽  
Bubble Plume ◽  
Air Void ◽  
Work Done

We present the turbulent kinetic energy (t.k.e.) budget of a dilute bubble plume in its asymptotic state. The budget is derived from an experimental dataset of bubble plumes formed inside an unstratified water tank. The experiments cover both the adjustment phase and asymptotic state of the plume. The diameters $d$ of air bubbles are in the range 1–4 mm and the air void fraction $\unicode[STIX]{x1D6FC}_{g}$ is between 0.7 % and 1.8 %. We measured the three components of the instantaneous liquid velocity vector with a profiling acoustic Doppler velocimeter. From the experiments, we found the following inside the heterogeneous bubble core of the plume: (i) the probability density functions of the standardized liquid fluctuations are very similar to those of homogeneous bubble swarms rising with and without background liquid turbulence; (ii) the characteristic temporal frequency $f_{cwi}$ at which bubbles inject t.k.e. into the liquid agrees with the prediction $f_{cwi}=0.14u_{s}/d$ observed and theoretically derived for homogeneous bubble swarms ($u_{s}$ is the bubble slip velocity); (iii) the liquid turbulence is anisotropic with the ratio of turbulence intensities between the vertical and horizontal components in the range 1.9–2.1; (iv) the t.k.e. production by air bubbles is much larger than that by liquid mean shear; and (v) an increasing fraction of the available work done by bubbles is deposited into liquid turbulence as one moves away from the plume centreline. Together with the existing knowledge of homogeneous bubble swarms, our results of the heterogeneous bubble plume support the view that millimetre-sized bubbles create specific patterns of liquid fluctuations that are insensitive to flow conditions and can therefore be possibly modelled by a universal form.

scholarly journals Experimental Investigation on Chemical Grouting in a Permeated Fracture Replica with Different Roughness

2019 ◽  
Vol 9 (13) ◽  
pp. 2762 ◽  
Author(s):  
Lichuang Jin ◽  
Wanghua Sui ◽  
Jialu Xiong
Keyword(s):  
Experimental Investigation ◽  
Water Flow ◽  
Flow Rate ◽  
Orthogonal Experiment ◽  
Water Flow Rate ◽  
Flowing Water ◽  
Gel Time ◽  
Initial Water ◽  
Chemical Grouting ◽  
Fracture Opening

This paper presents an experimental investigation on chemical grouting in a permeated fracture replica considering its roughness. Tests of grouting with flowing water in the fracture replica were carried out under different Bardon’s standard roughness profiles. The interactions between influential factors were considered and an experimental platform for grouting in rough fractures with flowing water was established. The effect of chemical grouting in fractures with flowing water was investigated using orthogonal experiment. The joint roughness coefficient (JRC), the initial water flow rate, the gel time, and the fracture opening were selected as factors in the orthogonal experiment. The results show that there is a positive correlation between the water plugging rate and JRC, and negative correlations between the water plugging rate and the initial water flow rate, gel time, and fracture opening. The change curve of the water flow rate is divided into three categories: Single platform decreasing type, double platform decreasing type, and multi-peak fluctuating type. The curve of seepage pressure contains three categories: Single peak type, multi-peak type and platform type. The results provide a reference for grouting in rock fractures.

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