Efficiency analysis of bubble pulsation formed by high-voltage discharge in nonfree field water

Dong, Yan; Bian, Decun; Zhao, Jinchang; Yin, Zhiqiang; Jia, Shuang; Feng, Jianfeng

doi:10.1177/1687814016663391

Cited by 5 publications

(5 citation statements)

References 4 publications

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“…The explosion of explosive will generate hightemperature and high-pressure explosive gas. In the generation of CSW, the release of energy will instantly vaporize and ionize water, resulting in bubble pulsation (Yan et al 2014;Hu et al 2021). The intensity of bubble pulsation is similar to that of high-temperature and high-pressure explosive gas produced by explosives (Gao et al 2003;Li et al 2019b).…”

Section: Mechanism Of Coal Permeability Enhancement By Shock Wave Fra...mentioning

confidence: 94%

Research advances in enhanced coal seam gas extraction by controllable shock wave fracturing

Fan,

Sun,

et al. 2024

Int J Coal Sci Technol

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With the continuous increase of mining in depth, the gas extraction faces the challenges of low permeability, great ground stress, high temperature and large gas pressure in coal seam. The controllable shock wave (CSW), as a new method for enhancing permeability of coal seam to improve gas extraction, features in the advantages of high efficiency, eco-friendly, and low cost. In order to better utilize the CSW into gas extraction in coal mine, the mechanism and feasibility of CSW enhanced extraction need to be studied. In this paper, the basic principles, the experimental tests, the mathematical models, and the on-site tests of CSW fracturing coal seams are reviewed, thereby its future research directions are provided. Based on the different media between electrodes, the CSW can be divided into three categories: hydraulic effect, wire explosion and excitation of energetic materials by detonating wire. During the process of propagation and attenuation of the high-energy shock wave in coal, the shock wave and bubble pulsation work together to produce an enhanced permeability effect on the coal seam. The stronger the strength of the CSW is, the more cracks created in the coal is, and the greater the length, width and area of the cracks being. The repeated shock on the coal seam is conducive to the formation of complex network fracture system as well as the reduction of coal seam strength, but excessive shock frequency will also damage the coal structure, resulting in the limited effect of the enhanced gas extraction. Under the influence of ground stress, the crack propagation in coal seam will be restrained. The difference of horizontal principal stress has a significant impact on the shape, propagation direction and connectivity of the CSW induced cracks. The permeability enhancement effect of CSW is affected by the breakage degree of coal seam. The shock wave is absorbed by the broken coal, which may hinder the propagation of CSW, resulting in a poor effect of permeability enhancement. When arranging two adjacent boreholes for CSW permeability enhancement test, the spacing of boreholes should not be too close, which may lead to negative pressure mutual pulling in the early stage of drainage. At present, the accurate method for effectively predicting the CSW permeability enhanced range should be further investigated.

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Section: Mechanism Of Coal Permeability Enhancement By Shock Wave Fra...mentioning

confidence: 94%

Research advances in enhanced coal seam gas extraction by controllable shock wave fracturing

Fan,

Sun,

et al. 2024

Int J Coal Sci Technol

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“…Так, авторы [16] видят перспективу использования такого многоволнового воздействия в медицине. Исследованию волны сжатия первого этапа посвящены работы [17,18], а пульсации ПГП изучались в [16,[19][20][21].…”

Section: анализ проблемыunclassified

“…Так, в работе [19] проведенные экспериментальные исследования позволили определить влияние накопленной в конденсаторах энергии и длины межэлектродного промежутка на развитие ПГП в разрядной камере размерами 500×500×500 мм. В цилиндрической камере внутренним диаметром 100 мм проводились экспериментальные исследования, которые позволили установить влияние гидростатического давления и зарядного напряжения на после-разрядные гидродинамические процессы [21]. Однако в работах не выполнялось сравнение характеристик развития ПГП в условиях ограниченного и неограниченного объема и не рассматривались различные способы осуществления ВЭВ в жидкости.…”

Section: анализ проблемыunclassified

Investigation of the Influence of a Limited Volume on the Pulsation of a Vapor-Gas Cavity During a High-Voltage Electric Explosion in a Liquid

Smirnov,

Khvoshchan,

Denisyuk

2024

EOM

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The influence of a limited volume on the hydrodynamic post-discharge processes during a high-voltage electric explosion (HVEE) and an explosion of a thin initiating conductor (ETIC) in a liquid is estimated, and the dynamics of a vapor-gas cavity (VGC) under those conditions is studied. Experimental studies have shown the advantage of the HVEE in comparison with the ETIC in terms of the energy contributed into the VGC expressed in an increase of the period of the VGC pulsation up to 55%. It was noted that with the ETIC in a limited volume of the discharge chamber, the period of pulsation of the VGC decreases up to 7.5 times compared to that of the ETIC in an unlimited space under the same initial conditions. A method for calculating the quasi-static pressure during an electric explosion in a limited volume with limited geometric parameters was proposed. The correlation between the calculated quasi-static pressure and the amplitude of the generated first compression wave is mentioned.

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“…The space between the positive and negative electrodes was 5 mm. The voltage threshold can be set manually and discharge of the electrodes in water was conducted using a transmission cable and then recorded by the test system [13]. Figure 5 shows the shock wave test platform for high voltage discharge in water.…”

Section: Equipmentmentioning

confidence: 99%

Normal Reflection Characteristics of One-Dimensional Unsteady Flow Shock Waves on Rigid Walls from Pulse Discharge in Water

Dong

Zhao

Niu

2017

Shock and Vibration

Self Cite

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Strong shock waves can be generated by pulse discharge in water, and the characteristics due to the shock wave normal reflection from rigid walls have important significance to many fields, such as industrial production and defense construction. This paper investigates the effects of hydrostatic pressures and perturbation of wave source (i.e., charging voltage) on normal reflection of one-dimensional unsteady flow shock waves. Basic properties of the incidence and reflection waves were analyzed theoretically and experimentally to identify the reflection mechanisms and hence the influencing factors and characteristics. The results indicated that increased perturbation (i.e., charging voltage) leads to increased peak pressure and velocity of the reflected shock wave, whereas increased hydrostatic pressure obviously inhibited superposition of the reflection waves close to the rigid wall. The perturbation of wave source influence on the reflected wave was much lower than that on the incident wave, while the hydrostatic pressure obviously affected both incident and reflection waves. The reflection wave from the rigid wall in water exhibited the characteristics of a weak shock wave, and with increased hydrostatic pressure, these weak shock wave characteristics became more obvious.

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Efficiency analysis of bubble pulsation formed by high-voltage discharge in nonfree field water

Cited by 5 publications

References 4 publications

Research advances in enhanced coal seam gas extraction by controllable shock wave fracturing

Research advances in enhanced coal seam gas extraction by controllable shock wave fracturing

Investigation of the Influence of a Limited Volume on the Pulsation of a Vapor-Gas Cavity During a High-Voltage Electric Explosion in a Liquid

Normal Reflection Characteristics of One-Dimensional Unsteady Flow Shock Waves on Rigid Walls from Pulse Discharge in Water

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