scholarly journals Analysis of the Influencing Factors of the Hydroxyl Radical Yield in a Hydrodynamic Cavitation Bubble of a Chitosan Solution Based on a Numerical Simulation

ACS Omega ◽  
2021 ◽  
Vol 6 (5) ◽  
pp. 3736-3744
Author(s):  
Xiangyu Zhang ◽  
Xinfeng Zhu ◽  
Yan Cao ◽  
Kunming Zhang ◽  
Yongchun Huang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Hydroxyl Radical ◽  
Influencing Factors ◽  
Cavitation Bubble ◽  
Chitosan Solution ◽  
Hydrodynamic Cavitation ◽  
Radical Yield

Numerical Simulation on the Dynamics for the Ultrasonic Cavitation Bubble in Chitosan Solution

2013 ◽  
Vol 275-277 ◽  
pp. 628-634
Author(s):  
Yong Chun Huang ◽  
Yu Wu ◽  
Feng Yang
Keyword(s):  
Numerical Simulation ◽  
Cavitation Bubble ◽  
Ambient Pressure ◽  
Bubble Radius ◽  
Chitosan Solution ◽  
Ultrasonic Cavitation ◽  
Single Frequency ◽  
Bubble Motion ◽  
Dual Frequency ◽  
Cavitation Intensity

In order to understand the influencing factors and laws on the ultrasonic cavitation dynamics in chitosan solution, numerical simulation of cavitation bubble motion had been performed based on Rayleigh-Plesset equation and the equation was solved by using 4~5 order Runge–Kutta algorithm. By numerical simulation the effects of frequency and intensity of ultrasonic, ambient pressure, initial bubble radius, concentration and temperature of solution, dual-frequency ultrasonic on the motion of cavitation bubble were discussed. The results show that for improving the effect of cavitation in chitosan solution, ultrasonic cavitation should be under the conditions of lower frequency, lower intensity, lower ambient pressure, smaller initial cavitation bubble, moderate temperature of solution and lower concentration. It is also found that the cavitation intensity due to dual-frequency ultrasonic is stronger than that of single-frequency ultrasonic.

Luminescent Spots Induced by a Cavitating Jet

2011 ◽  
Author(s):  
Hitoshi Soyama
Keyword(s):  
Hydroxyl Radical ◽  
Hot Spots ◽  
Cavitation Bubble ◽  
High Speed ◽  
Acoustic Cavitation ◽  
Water Jet ◽  
Hydrodynamic Cavitation ◽  
Electron Multiplication ◽  
Luminescence Analyzer ◽  
Cavitating Jet

As cavitation bubble collapses cause hot spots and/or radicals such as hydroxyl radical, luminescence was observed at bubble collapsing region. The luminescence induced by acoustic cavitation is named as sonoluminescence. In the present paper, luminescence induced by hydrodynamic cavitation was investigated. In order to generate hydrodynamic cavitation, a high-speed water jet was injected into a water-filled chamber. This sort of the jet with cavitation is called as a cavitating jet. The intensity of luminescence of the cavitating jet was evaluated by a luminescence analyzer and the aspect of the cavitating jet was observed by a cooled electron multiplication charged-coupled device camera. It was revealed that the luminescent spots induced by the cavitating jet were observed by the camera.

Soil-pH and cement influence the weathering kinetics of chrysotile asbestos in soils and its hydroxyl radical yield

2021 ◽  
pp. 128068
Author(s):  
Martin Walter ◽  
Gerald Geroldinger ◽  
Lars Gille ◽  
Stephan M. Kraemer ◽  
Walter D.C. Schenkeveld
Keyword(s):  
Hydroxyl Radical ◽  
Soil Ph ◽  
Chrysotile Asbestos ◽  
Kinetics Of ◽  
Radical Yield

scholarly journals On the Nature of Hydrodynamic Cavitation Process and Its Application for the Removal of Water Pollutants

2019 ◽  
Vol 12 ◽  
pp. 117862211988048 ◽  
Author(s):  
Erick R Bandala ◽  
Oscar M Rodriguez-Narvaez
Keyword(s):  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
High Energy ◽  
Optimal Operation ◽  
Hydrodynamic Cavitation ◽  
Radical Scavenger ◽  
Process Conditions ◽  
Cavitation Process ◽  
Operation Conditions ◽  
Hydroxyl Radical Scavenger

Cavitation is considered a high energy demanding process for water treatment. For this study, we used a simple experimental setup to generate cavitation at a low pressure (low energy) and test it for hydroxyl radical production using a well-known chemical probe as a hydroxyl radical scavenger. The conditions for generating the cavitation process (eg, pressure, flow velocity, temperature, and other significant variables) were used to degrade model contaminants, an azo dye and an antibiotic. The amount of hydroxyl radicals generated by the system was estimated using N,N-dimethyl-p-nitrosoaniline (pNDA) as hydroxyl radical scavenger. The capability of hydrodynamic cavitation (HC) to degrade contaminants was assessed using Congo red (CR) and sulfamethoxazole (SMX) as model contaminants. Different chemical models were analyzed using UV-visible spectrophotometry (for pNDA and CR) and high-performance liquid chromatography (HPLC) (for SMX) after HC treatment under different process conditions (ie, pressure of 13.7 and 10.3 kPa, and flow rates of 0.14 to 3.6 × 10−4 m3/s). No pNDA bleaching was observed for any of the reaction conditions tested after 60 minutes of treatment, which suggests that there was no hydroxyl radical generation during the process. However, 50% degradation of CR and 25% degradation of SMX were observed under the same process conditions, comparable with previously reported results. These results suggest that the process is most likely thermally based rather than radically based, and therefore, it can degrade organic pollutants even if no hydroxyl radicals are produced. Hydrodynamic cavitation, either alone or coupled with other advanced water technologies, has been identified as a promising technology for removing organic contaminants entering the water cycle; however, more research is still needed to determine the specific mechanisms involved in the process and the optimal operation conditions for the system.

Numerical Simulation Study on the Key Influencing Factors of Water-Invasion Performance for the Gas Wells with Bottom-Water

2014 ◽  
Vol 884-885 ◽  
pp. 104-107
Author(s):  
Zhi Jun Li ◽  
Ji Qiang Li ◽  
Wen De Yan
Keyword(s):  
Numerical Simulation ◽  
Influencing Factors ◽  
Bottom Water ◽  
Simulation Method ◽  
Gas Production ◽  
Production Performance ◽  
Gas Wells ◽  
Two Phase ◽  
Gas Well ◽  
Water Gas

For the water-sweeping gas reservoir, especially when the water-body is active, water invasion can play positive roles in maintaining formation pressure and keeping the gas well production. But when the water-cone break through and towards the well bottom, suffers from the influencing of gas-water two phase flows, permeability of gas phase decrease sharply and will have a serious impact on the production performance of the gas well. Moreover, the time when the water-cone breakthrough will directly affect the final recovery of the gas wells, therefore, the numerical simulation method is used to conduct the research on the key influencing factors of water-invasion performance for the gas wells with bottom-water, which is the basis of the mechanical model for the typical gas wells with bottom-water. It indicate that as followings: (1) the key influencing factors of water-invasion performance for the gas wells with bottom-water are those, such as the open degree of the gas beds, well gas production and the amount of Kv/Kh value; and (2) the barrier will be in charge of great significance on the water-controlling for the bottom water gas wells, and its radius is the key factor to affect water-invasion performance for the bottom water gas wells where the barriers exist nearby.

The effect of NCG on the characteristics of hydraulic cavitation

2020 ◽  
Vol 21 (5) ◽  
pp. 504
Author(s):  
Qiang Li ◽  
Wei Li ◽  
Jian Zhang ◽  
Dezhi Ming ◽  
Weiwei Xu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Cavity Length ◽  
Volume Fraction ◽  
Venturi Tube ◽  
Hydrodynamic Cavitation ◽  
Cavitation Model ◽  
Noncondensable Gas ◽  
Hydrodynamic Phenomenon ◽  
Increasing Temperature

Hydraulic cavitation, as an important and complex hydrodynamic phenomenon, has long drawn attention. In this paper, the ZGB (Zwart-Gerber-Belamri) cavitation model is improved and the effect of NCG (noncondensable gas) on cavitation in water is studied by numerical simulation. The influence of NCG on the cavity length, the temperature of the cavities and the mixed viscosity of the cavities is investigated through the improved ZGB cavitation model. In addition, experiments on hydrodynamic cavitation produced by a Venturi tube are used to validate the improved ZGB cavitation model. The results show that NCG not only shortens the length of the cavity but also reduces the volume fraction of the vapor. The existence of NCG decreases the viscosity in the cavity of the Venturi tube but increases the viscosity at the sidewall of the tube. In addition, the temperature in the cavities increases with increasing NCG. Regardless of whether air is injected, the volume fraction of the vapor in the cavities increases first and then decreases with increasing temperature. However, the transition temperature decreases somewhat after injecting air. Therefore, the influence of NCG on hydraulic cavitation is significant, and the role of NCG should be considered in industry.

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