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Effect of cavitation bubble collapse on hydraulic oil temperature

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Journal of Central South University 2016年第7期23卷 1657-1668页

作者：沈伟张健孙毅张迪嘉姜继海 Department of Mechatronics Engineering University of Shanghai for Science and TechnologyShanghai 200093China Department of Mechatronics Engineering Harbin University of CommerceHarbin 150000China Beijing Institute of Precision Mechatronics and Control Equipment Beijing 100076China School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150000China

Cavitation bubble collapse has a great influence on the temperature of hydraulic oil. Herein, cone-type throttle valve experiments are carried out to study the thermodynamic processes of cavitation. First, the processes of growth and collapse are analysed, and the relationships between the hydraulic oil temperature and bubble growth and collapse are deduced. The effect of temperature is then considered on the hydraulic oil viscosity and saturated vapour pressure. Additionally, an improved form of the Rayleigh–Plesset equation is developed. The effect of cavitation on the hydraulic oil temperature is experimentally studied and the effects of cavitation bubble collapse in the hydraulic system are summarised. Using the cone-type throttle valve as an example, a method to suppress cavitation is proposed.

关键词： cavitation bubble collapse hydraulic oil temperature Rayleigh-Plesset equation cone-type throttle valve

Pseudopotential multi-relaxation-time lattice Boltzmann model for cavitation bubble collapse with high density ratio

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Chinese Physics B 2016年第10期25卷 189-196页

作者：单鸣雷朱昌平姚澄殷澄蒋小燕 College of Internet of Things Engineering Hohai University Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai University

The dynamics of the cavitation bubble collapse is a fundamental issue for the bubble collapse application and prevention. In the present work, the modified forcing scheme for the pseudopotential multi-relaxation-time lattice Boltzmann model developed by Li Q et al. [ Li Q, Luo K H and Li X J 2013 Phys. Rev. E 87 053301] is adopted to develop a cavitation bubble collapse model. In the respects of coexistence curves and Laplace law verification, the improved pseudopotential multi-relaxation-time lattice Boltzmann model is investigated. It is found that the thermodynamic consistency and surface tension are independent of kinematic viscosity. By homogeneous and heterogeneous cavitation simulation, the ability of the present model to describe the cavitation bubble development as well as the cavitation inception is verified. The bubble collapse between two parallel walls is simulated. The dynamic process of a collapsing bubble is consistent with the results from experiments and simulations by other numerical methods. It is demonstrated that the present pseudopotential multirelaxation-time lattice Boltzmann model is applicable and efficient, and the lattice Boltzmann method is an alternative tool for collapsing bubble modeling.

关键词： lattice Boltzmann method pseudopotential model bubble collapse improved forcing scheme

Investigation of cavitation bubble collapse near rigid boundary by lattice Boltzmann method

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Journal of Hydrodynamics 2016年第3期28卷 442-450页

作者：单鸣雷朱昌平周曦殷澄韩庆邦 College of Internet of Things Engineering and Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai University

The dynamics of the bubble collapse near a rigid boundary is a fundamental issue for the bubble collapse application and prevention. In this paper, the bubble collapse is modeled by adopting the lattice Boltzmann method （LBM） and is verified, and then the dynamic characteristics of the collapsing bubble with the second collapse is investigated. The widely used Shan-Chen model in the LBM multiphase community is modified by coupling with the Carnahan-Starling equation of state （C-S EOS） and the exact difference method （EDM） for the forcing term treatment. The simulation results of the bubble profile evolution by the LBM are in excellent agreements with the theoretical and experimental results. From the two-dimensional pressure field evolution, the dynamic characteristics of the different parts during the bubble collapse stage are studied. The role of the second collapse in the rigid boundary damage is discussed, and the impeding effect between two collapses is demonstrated.

关键词： cavitation mechanics lattice Boltzmarm method bubble collapse rigid boundary

Investigation of cavitation erosion caused by laser-induced single bubble collapse near alloy coating surface

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Journal of Hydrodynamics 2023年第5期35卷 876-886页

作者： Hai-gang Wen Zhi-feng Yao Qin Wu Yu-rong Sun Chen-xi Yang Qiang Zhong College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System China Agricultural UniversityBeijing100083China School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China

To investigate the mechanism of cavitation erosion caused by laser-induced single bubble near the surface coating alloy coating material, we utilized a nanosecond resolution photography system based on a Q-switched Nd: YAG laser and conventional industrial camera to carefully observe the transient process of bubble collapse under different conditions. We analyzed the generation of collapse microjets and the emission of collapse shock waves and explored the cavitation erosion characteristics caused by laser-induced single bubble collapse. We discovered that even on surfaces of highly hard and corrosion-resistant alloy coatings, severe cavitation erosion occurred, and there was a phenomenon of mismatch between the cavitation erosion location and the bubble projection position. The intensity of cavitation erosion depended on the energy self-focusing effect of the collapse shockwaves. In the experiments, we also observed the self-focusing phenomenon of collapse shockwaves under different conditions. The self-focusing effect of collapse shockwaves weakened as the distance between the bubble and the material surface increased, which may be the cause of cavitation erosion induced by a laser-induced single bubble.

关键词： Cavitation erosion bubble collapse laser-induced shock wave self-focusing effect

Simulation of Heat Transfer with the Growth and collapse of a Cavitation bubble Near the Heated Wall

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Journal of Thermal Science 2013年第4期22卷 352-358页

作者： Bin Liu Jun Cai Fengchao Li Xiulan Huai Institute of Engineering Thermophysics Chinese Academy of Sciences University of Chinese Academy of Sciences

The growth and collapse behaviors of a single cavitation bubble near a heated wail and its effect on the heat transfer are numerically investigated. The present study is designed to reveal the mechanism of cavitation enhanced heat transfer from a microscopic perspective. In the simulation, the time-dependent Navier-Stokes equations are solved in an axisymmetric two-dimensional domain. The volume of fluid （VOF） method is employed to track the liquid-gas interface. It is assumed that the gas inside the bubble is compressible vapor, and the sur- rounding liquid is incompressible water. Mass transfer between two phases is ignored. The eaiculated bubble pro-files were compared to the available experimental data, and a good agreement was obtained. Then, the relationship among bubble motion, flow field and surface heat transfer coefficient was analyzed. On this basis, the effects of such factors as the initial distance between the bubble and the wall, the initial vapor pressure and the initial bubble nucleus size on the heat transfer enhancement are discussed. The present study is helpful to understand the heat transfer phenomenon in presence of cavitation bubble in liquid.

关键词： cavitation bubble bubble growth bubble collapse heat transfer enhancement

Research on the collapse process of a near-wall bubble

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Journal of Hydrodynamics 2023年第5期35卷 899-912页

作者： Bing Zhu Wang Han Wen-jun Xu Wei Zhang University of Shanghai for Science and Technology Shanghai200093China Shanghai Key Laboratory of Power Energy in Multiphase Flow and Heat Transfer Shanghai200093China Marine Design and Research Institute of China Shanghai200011China

The effect of wall on the bubble collapse is significant. A compressible numerical simulation method based on the state equation was used to numerically calculate the collapse process of bubbles at different leaving wall distances. The results show that when the dimensionless distance between the bubble center and the wall is greater than zero, the bubble generates a high-pressure region at the top of the interface, which induces a jet toward the wall. When the dimensionless distance is less than zero, the jet is generated from the vicinity of the contact position between the bubble and the wall and moves along the wall towards the center axis of the bubble. When the dimensionless distance is equal to zero, that is, the center of the bubble coincides with the center of the wall, the bubble shrinks uniformly, and its collapse process is consistent with that of a single bubble in free space under the same parameter conditions. Comparison of these three typical cases of dimensionless distance from the wall reveals that the presence of the wall induces an asymmetric effect and a pressure gradient effect in the flow field around the bubble, and the farthest point away from the center of the attached wall is a high-pressure region, which induces destabilization of the bubble interface and the occurrence of jets.

关键词： bubble collapse compressible simulation shock wave propagation jet flow direction

Energy partition in laser-induced cavitation bubbles near the rigid wall with a gas-containing hole

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Journal of Hydrodynamics 2024年第3期36卷 435-443页

作者： Dong-qiao He Hai-gang Wen Si-yuan Geng Chen-xi Yang Qiang Zhong Zhi-feng Yao College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China PowerChina Beijing Engineering Corporation Limited Beijing100024China State Key Laboratory of Efficient Utilization of Agricultural Water Resources Beijing100083China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System China Agricultural UniversityBeijing100083China

To investigate the energy partition in laser-induced cavitation bubbles near the rigid wall with a gas-containing hole,we utilized a nanosecond resolution photography system based on a Q-switched Nd:YAG laser and conventional industrial camera to carefully observe the transient process of bubble collapse near the rigid wall with a gas-containing *** analyzed the generation of collapse microjets and the emission of collapse shock *** found that the cavitation bubble near the rigid wall with a gas-containing hole collapsed at different times and space,and produced various types of shock *** on the far field pressure information of the shock waves measured by hydrophone,the energy of the shock waves generated by the bubble collapse near the rigid wall with a gas-containing hole is calculated for the first *** results show that the ratio of collapse shock wave energy to bubble energy is approximately between 0.7 and 0.8.

关键词： Energy partition bubble collapse laser-induced shock wave gas-containing hole

Influence of physical parameters on the collapse of a spherical bubble

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Theoretical & Applied Mechanics Letters 2022年第6期12卷 395-402页

作者： Bo-Hua Sun School of Civil Engineering&Institute of Mechanics and Technology Xi’an University of Architecture and TechnologyXi’an 710055China

This paper examines the influence of physical parameters on the collapse dynamics of a spherical bubble filled with diatomic gas(κ=7/5).The problem is formulated by the Rayleigh–Plesset dynamical equation,whose numerical solutions are carried out by *** studies show that each physical parameter affects the bubble collapse dynamics in different degree,which reveals that bubble collapse dynamics must considers all the parameters including liquid viscosity,surface tension,etc,else the outcome cannot be trusted.

关键词： bubble collapse Rayleigh's modeling Physical parameters Numerical simulation Maple

Effect of micro-clearance structure on the collapse of individual liquid hydrogen bubbles

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Energy Storage and Saving 2024年第3期3卷 231-241页

作者： Shaohang Yan Qi Zhao Tianwei Lai Yu Hou School of Energy and Power Engineering Xi’an Jiaotong UniversityXi’an710049China MOE Key Laboratory of Cryogenic Technology and Equipment Xi’an Jiaotong UniversityXi’an710049China

Cavitation occurs in the micro-clearance of liquid-hydrogen-lubricated bearings owing to the pressure drop caused by high-speed *** pressure undulation caused by cavitation collapse results in bearing surface erosion and significantly affects the bearing *** this study,a modified Z-G-B cavitation model was used to study the crushing process of a single liquid hydrogen bubble in a shear *** Fourier transform(FFT)and wavelet transform(WT)were applied to study the frequency characteristics of the pressure,mass transfer rate,and vapor mass fraction during bubble rupture in shearing *** obtain a deeper insight into the details of the effect of the shear micro-clearance structure on bubble collapse,the relationship between the flow field energy,attenuation rate,and frequency was *** proper orthogonal decomposition(POD)and dynamic mode decomposition(DMD)methods were used to analyze the energy of each order mode of the flow *** analysis results of the bubble vibration intensity with respect to time and frequency provide a theoretical basis for the optimization of the bearing structure.

关键词： Liquid hydrogen bubble collapse Shearing micro-clearance Wavelet transform Flow field analysis