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Physics of cavitation near particles

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Journal of Hydrodynamics 2024年第1期36卷 102-118页

作者： jia-xin yu Xiao-yu Wang Jun-wei Shen Jin-sen Hu Xiang-qing Zhang Da-qing He yu-ning Zhang Key Laboratory of Power Station Energy Transfer Conversion and System(Ministry of Education) School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

The combined effect of cavitation and silt abrasion presents a great challenge and threat to secure the operation and the efficiency of hydraulic machineries working in sediment-laden fluid.The present paper critically reviews the current research progress on the interaction mechanisms of the bubbles and the particles.Firstly,the analytical models including boundary treatment methods for predicting the jet dynamics of the bubble collapse near particles are demonstrated.Secondly,the bubble collapsing dynamics,jet dynamics and shock wave characteristics near particles are revealed both experimentally and numerically.Finally,the bubble-particle-wall system is investigated with a focus on microjets.

关键词： Cavitation bubble particle jet shock wave

Blast performance of layered charges enveloped by aluminum powder/rubber composites in confined spaces

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Defence Technology（防务技术） 2022年第4期18卷 583-592页

作者： Jun-bao Li Wei-bing Li jia-xin yu Wei Xiao He-yang Xu ZNDY of Ministerial Key Laboratory Nanjing University of Science and TechnologyNanjing210094China School of Chemical Engineering Nanjing University of Science and TechnologyNanjing210094China

A layered charge composed of the JH-2 explosive enveloped by a thick-walled cylindrical casing(active aluminum/rubber and inert lithium fluoride/rubber composites) was designed and explosion experiments were conducted in a 1.3 m3tank and a 113 m3bunker.The blast parameters,including the quasistatic pressure(ΔpQS),special impulse(I),and peak overpressure(Δpmax),and images of the explosion process were recorded,and the influence of the Al content(30% and 50%) and Al particle size(1,10,and 50 μm) on the energy release of aluminum/rubber composites were investigated.The results revealed that the use of an active layer increased the peak overpressure generated by the primary blast wave,as well as the quasistatic pressure and special impulse related to fuel burning within tens of milliseconds after detonation.When the Al content was increased from 30% to 50%,the increases of ΔpQS and I were not obvious,and Δpmaxeven decreased,possibly because of decreased combustion efficiency and greater absorption of the blast wave energy for layers with 50% Al.Compared with the pure JH-2charge,the charge with 1 μm Al particles produced the highest Δpmax,indicating that better transient blast performance was generated by smaller Al particles.However,the charge with 10 μm Al particles showed the largest ΔpQSand I,suggesting that a stronger destructive effect occurred over a longer duration for charges that contained moderate 10 μm Al.

关键词： Confined explosion Aluminum powder/rubber composites Layered charge Blast parameters

Theoretical investigation on the cavitation bubble dynamics near three spherical particles based on Weiss theorem

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Journal of Hydrodynamics 2023年第6期35卷 1119-1130页

作者： yu-ning Zhang Zhi-ling Ding Jing-rong Hu Xiao-xiao Zheng jia-xin yu Jin-sen Hu College of Mechanical and Transportation Engineering China University of Petroleum-BeijingBeijing102249China Beijing Key Laboratory of Process Fluid Filtration and Separation China University of Petroleum-BeijingBeijing102249China China Fire and Rescue Institute Beijing102202China Key Laboratory of Power Station Energy Transfer Conversion and System(Ministry of Education) School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

To research the dynamics of the cavitation bubble under the interaction of particle clusters,the bubble morphological evolutionary characteristics near three equal-sized spherical particles are theoretically explored in the present study based on the Weiss theorem and the velocity potential superposition theory.The three particles are arranged symmetrically,and the fluid velocity field near the three particles and the cavitation bubble is obtained.Moreover,the effects of the bubble-particle distance and the maximum radius of the cavitation bubble on the fluid velocity are investigated,and the contribution mechanisms of the fluid velocity field constituents are compared.The analysis has found that:(1)The fluid velocity between the bubble and the particle is lower than that at the other locations in both the growth and collapse phases,thus the bubble cannot always maintain a standard spherical shape.(2)The bubble-particle distance and the maximum radius of the cavitation bubble are the key parameters affecting the circumferential inhomogeneity of the radial velocity of the fluid around the bubble.The larger the maximum radius or the smaller the bubble-particle distance is,the more visible the non-circularity of the bubble morphology.(3)The image bubbles and the linear sinks contribute oppositely to the fluid velocity field,and the presence of the image bubble reduces the fluid velocity.In the low velocity region,the image bubble is the main mechanism contributing to the effect of the particle on the fluid velocity.

关键词： Particles-bubble effects velocity potential fluid velocity bubble morphology Weiss theorem

Blast wave characteristics of multi-layer composite charge:Theoretical analysis,numerical simulation,and experimental validation

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Defence Technology（防务技术） 2023年第1期19卷 91-102页

作者： Jun-bao Li Wei-bing Li Xiao-wen Hong jia-xin yu jian-jun Zhu ZNDY of Ministerial Key Laboratory Nanjing University of Science and TechnologyNanjing210094China Inner Mongolia Metal Material Research Institute Yantai264003China China Ship Development and Design Center Wuhan 430064China

This article investigates the characteristics of shock wave overpressure generated by multi-layer composite charge under different detonation modes.Combining dimensional analysis and the explosion mechanism of the charge,a peak overpressure prediction model for the composite charge under singlepoint detonation and simultaneous detonation was established.The effects of the charge structure and initiation method on the overpressure field characteristics were investigated in AUTODYN simulation.The accuracy of the prediction model and the reliability of the numerical simulation method were subsequently verified in a series of static explosion experiments.The results reveal that the mass of the inner charge was the key factor determining the peak overpressure of the composite charge under single-point detonation.The peak overpressure in the radial direction improved apparently with an increase in the aspect ratio of the charge.The overpressure curves in the axial direction exhibited a multi-peak phenomenon,and the secondary peak overpressure even exceeded the primary peak at distances of 30D and 40D(where D is the charge diameter).The difference in peak overpressure among azimuth angles of 0-90°gradually decreased with an increase in the propagation distance of the shock wave.The coupled effect of the detonation energy of the inner and outer charge under simultaneous detonation improved the overpressure in both radial and axial directions.The difference in peak overpressure obtained from model prediction and experimental measurements was less than 16.4%.

关键词： Blast wave characteristics Multi-layer composite charge Dimensional analysis AUTODYN mapping Model Explosion experiment

Laser-induced cavitation bubble near boundaries

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Journal of Hydrodynamics 2023年第5期35卷 858-875页

作者： jia-xin yu Xiao-yu Wang Jin-sen Hu Jun-wei Shen Xiang-qing Zhang Xiao-xiao Zheng yu-ning Zhang Zhi-feng Yao Key Laboratory of Power Station Energy Transfer Conversion and System(Ministry of Education) School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China China Fire and Rescue Institute Beijing102202China College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China

Laser-induced cavitation bubble has been widely used to investigate the mechanisms of hydraulic machinery cavitation erosion and to explore applications in atomization, alloy strengthening, ultrasonic chemistry, biomedicine, surface cleaning and materials processing. This paper consolidates existing research findings on the cavitation bubble dynamics near different boundaries and provides insights for future research work. Firstly, the dynamics of a single cavitation bubble in an infinite field is presented. Subsequently, the focus shifts to the dynamics of cavitation bubble near a rigid wall, angular walls, particles and hydrofoil. Lastly, the paper delves into the dynamics of cavitation bubble within a droplet, revealing the microscopic mechanism of droplet breakup induced by cavitation bubble.

关键词： Laser-induced cavitation bubble bubble dynamics bubble-particle interactions droplet splash

Effect of quenching-partitioning treatment on the microstructure, mechanical and abrasive properties of high carbon steel

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International Journal of Minerals,Metallurgy and Materials 2021年第4期28卷 676-687页

作者： jian-ping Lai jia-xin yu Jiong Wang Key Laboratory of Testing Technology for Manufacturing Process in Ministry of Education Mianyang 621010China School of Manufacturing Science and Engineering Southwest University of Science and TechnologyMianyang 621010China Central Sichuan Oil-Gas District Petro-China Southwest Oil and Gas Field CompanySuining 629000China

The present work employed the X-ray diffraction, scanning electron microscopy, electron backscattered diffraction, and electron probe microanalysis techniques to identify the microstructural evolution and mechanical and abrasive behavior of high carbon steel during quenching-partitioning treatment with an aim to enhance the toughness and wear resistance of high carbon steel.Results showed that, with the increase in partitioning temperature from 250 to 400℃, the amount of retained austenite(RA) decreased resulting from the carbide precipitation effect after longer partitioning times.Moreover, the stability of RA generally increased because of the enhanced degree of carbon enrichment in RA.Given the factors affecting the toughness of high carbon steel, the stability of RA associated with size, carbon content, and morphology plays a significant role in determining the toughness of high carbon steel.The analysis of the wear resistance of samples with different mechanical properties shows that hardness is the primary factor affecting the wear resistance of high carbon steel, and the toughness is the secondary one.

关键词： high carbon steel quenching and partitioning microstructural evolution retained austenite

Distribution of reformed coke oven gas in a shaft furnace

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Journal of Iron and Steel Research(International) 2020年第12期27卷 1382-1390页

作者： xin jiang jia-xin yu Lin Wang Dong-wen Xiang Qiang-jian Gao Hai-yan Zheng Feng-man Shen School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina Department of Mechanical Engineering Shenyang Institute of EngineeringShenyang 110136LiaoningChina

In recent years, the reformed coke oven gas (COG) was proposed to be used as reducing gas in a shaft furnace. A mathematical model of gas flow based on the reformed COG was built. The effects of the pressure ratio of reducing gas to cooling gas (k) on the gas distribution in the shaft furnace were investigated. The calculation results show that k is an important operation parameter, which can obviously affect the gas distribution in the shaft furnace. The value of k should be compromised. Both too big and too small k values are not appropriate, and the most reasonable value for k is 1:1.33.Under this condition, the utilization coefficient of reducing gas, the utilization coefficient of cooling gas and the coefficient of upward gas are 0.94, 0.92 and 1.03, respectively. Based on the validation of physical experiments, the calculated values of the model agreed well with the physical experimental data. Thus, the established model can properly describe the reformed COG distribution in an actual shaft furnace.

关键词： Direct reduction Shaft furnace Coke oven gas Gas distribution Pressure ratio Reducing gas Cooling gas

Effect of Cycling Low Velocity Impact on Mechanical and Wear Properties of CFRP Laminate Composites

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Chinese Journal of Mechanical Engineering 2018年第6期31卷 45-54页

作者： Yang Sun Zhen-Bing Cai Song-Bo Wu jian-Hua Liu jia-xin yu Tribology Research Institute Key Lab of Advanced Technologies of Materials Southwest Jiaotong University Chengdu 610031 China Key Laboratory of Testing Technology for Manufacturing Process of Ministry of Education Southwest University of Science and Technology Mianyang 621010 China

The mechanical and wear properties of CFRP laminate were investigated using a method of cycling low velocity impact, to study the trend and mechanism of impact resistance of the CFRP laminate under repeated impact during its service process. The interface responses of CFRP laminate under di erent impact kinetic energy during the cycling impact process were studied were studied experimentally, such as impact contact duration, deformation and energy absorption. The worn surface morphologies were observed through optical microscopy and a 3?D surface profiler and the cross?sectional morphologies were observed through SEM to investigate the mechanism of impact material dam?age. Based on a single?degree?of?freedom damping vibration model, the normal contact sti ness and contact damp?ing of the material in di erent wear stages were calculated. It shows the failure process of CFRP laminate damaged by accumulated absorption energy under the cycling impact of di erent initial kinetic energy. The results indicate that the sti ness and damping coe cients will change at di erent impact velocities or cycle numbers. The damage mechanism of CFRP laminates under cycling low kinetic energy is delamination. After repeated experiments, it was found that there was a threshold value for the accumulated absorption energy before the failure of the CFRP laminate.

关键词： CFRP laminate Low velocity impact Impact resistance Accumulated absorption energy threshold Delamination

Tribological Behaviors of Electroless Nickel-Boron Coating on Titanium Alloy Surface

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 309-320页

作者： Yao jia jianping Lai jiaxin yu Huimin Qi Yafeng Zhang Hongtu He Key Laboratory of Testing Technology for Manufacturing Process in Ministry of Education State Key Laboratory of Environment-Friendly Energy MaterialsSouthwest University of Science and TechnologyMianyang 621010China

Titanium alloys are excellent structural materials in engineering fields,but their poor tribological properties limit their further applications.Electroless plating is an effective method to enhance the tribological performance of alloys,but it is difficult to efficiently apply to titanium alloys,due to titanium alloy’s strong chemical activity.In this work,the electroless Nickel-Boron(Ni-B)coating was successfully deposited on the surface of titanium alloy(Ti-6AL-4V)via a new pre-treatment process.Then,linearly reciprocating sliding wear tests were performed to evaluate the tribological behaviors of titanium alloy and its electroless Ni-B coatings.It was found that the Ni-B coatings can decrease the wear rate of the titanium alloy from 19.89×10^(−3)mm^(3)to 0.41×10^(−3)mm^(3),which attributes to the much higher hardness of Ni-B coatings.After heat treatment,the hardness of Ni-B coating further increases corresponding to coating crystallization and hard phase formation.However,heat treatment does not improve the tribological performance of Ni-B coating,due to the fact that higher brittleness and more severe oxidative wear exacerbate the damage of heat-treated coatings.Furthermore,the Ni-B coatings heat-treated both in air and nitrogen almost present the same tribological performance.The finding of this work on electroless coating would further extend the practical applications of titanium alloys in the engineering fields.

关键词： Electroless coating Titanium alloy Tribology Wear Heat treatment Nanoindentation