Bubble–bubble interaction effects on multiple bubbles dynamics in an ultrasonic cavitation field

2019 ◽  
Vol 234 (7) ◽  
pp. 1051-1060
Author(s):  
Feng Cheng ◽  
Weixi Ji ◽  
Junhua Zhao
Keyword(s):  
Cavitation Erosion ◽  
Threshold Value ◽  
Ultrasonic Field ◽  
Pressure Amplitude ◽  
Cavitation Field ◽  
Bubble Interaction ◽  
Erosion Test ◽  
Multiple Bubbles ◽  
Optimal Coupling ◽  
Material Fracture

A vibratory erosion test rig is used to study the cavitation erosion of 6061 alloy. Some craters and material fracture are found on the specimen surface at the beginning of test. A cavitation model in an ultrasonic field is developed by applying the bubble–bubble interaction effect into Keller–Miksis equation to obtain the bubbles dynamic characteristics. The results reveal that the bubble cloud configuration is suitable for the explanation of cavitation erosion, and the erosion surfaces of the specimen were subjected to the effect of both massive bubbles collapsing, occurring in the thin liquid layer between the horn and the specimen. It is concluded that the optimal coupling strength of bubbles increases with the decrease of the bubble initial radius, and stable cavitation only occurs when the acoustic pressure amplitude is higher than a threshold value, which can well predict the experimental results.

Nonlinear dynamics of a shell encapsulated microbubble near solid boundary in an ultrasonic field

2020 ◽  
Vol 14 (3) ◽  
pp. 7235-7243
Author(s):  
N.M. Ali ◽  
F. Dzaharudin ◽  
E.A. Alias
Keyword(s):  
Oscillation Amplitude ◽  
Ultrasonic Field ◽  
Dynamical Behaviour ◽  
Ultrasound Contrast Agents ◽  
Chaotic Behaviour ◽  
Solid Boundary ◽  
Driving Frequency ◽  
Pressure Amplitude ◽  
Radial Expansion ◽  
Therapeutic Delivery

Microbubbles have the potential to be used for diagnostic imaging and therapeutic delivery. However, the transition from microbubbles currently being used as ultrasound contrast agents to achieve its’ potentials in the biomedical field requires more in depth understanding. Of particular importance is the influence of microbubble encapsulation of a microbubble near a vessel wall on the dynamical behaviour as it stabilizes the bubble. However, many bubble studies do not consider shell encapsulation in their studies. In this work, the dynamics of an encapsulated microbubble near a boundary was studied by numerically solving the governing equations for microbubble oscillation. In order to elucidate the effects of a boundary to the non-linear microbubble oscillation the separation distances between microbubble will be varied along with the acoustic driving. The complex nonlinear vibration response was studied in terms of bifurcation diagrams and the maximum radial expansion. It was found that the increase in distance between the boundary and the encapsulated bubble will increase the oscillation amplitude. When the value of pressure amplitude increased the single bubble is more likely to exhibit the chaotic behaviour and maximum radius also increase as the inter wall-bubble distance is gradually increased. While, with higher driving frequency the maximum radial expansion decreases and suppress the chaotic behaviour.

Analysis of the External Conditions Affecting on the Cavitation Resistance of a Steel

2019 ◽  
Vol 946 ◽  
pp. 31-36
Author(s):  
Hussam L. Alwan ◽  
N. Lezhnin ◽  
Yury Korobov
Keyword(s):  
Surface Resistance ◽  
Cavitation Erosion ◽  
Medium Carbon Steel ◽  
Cavitation Resistance ◽  
Nacl Solution ◽  
Medium Carbon ◽  
Test Conditions ◽  
External Conditions ◽  
Erosion Test ◽  
Testing Liquid

The aim of this study is to analyze the effect of cavitation erosion test conditions on the surface resistance of medium carbon steel. The ultrasonic vibratory specimen system was used to perform the experiments under the laboratory conditions. The vibratory frequency and the displacement amplitude were 20 kHz and 20 μm, respectively. In design of experiments, four various cavitation behaviors have been studied based on four cavitation test conditions corresponding to those behaviors. These conditions can be summarized as follows: (1) the usage of water as a testing liquid; (2) replacement the water with 3.5% NaCl solution; (3) applying a certain voltage to cause a combined electrochemical action working simultaneously with the water; and (4) applying the same voltage by using the 3.5% NaCl solution instead of water. The obtained results showed that the mass loss differs by test modes applied.

The Cavitation Behavior of Fe-Cr-C-Si-Ni Alloys

2006 ◽  
Vol 510-511 ◽  
pp. 274-277
Author(s):  
Ji Hui Kim ◽  
Kwang Su Na ◽  
Seon Jin Kim
Keyword(s):  
Work Hardening ◽  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Hardfacing Alloy ◽  
Ni Alloys ◽  
Ni Addition ◽  
Work Hardening Rate ◽  
Erosion Test ◽  
Cavitation Behavior ◽  
Cavitation Erosion Resistance

The cavitation erosion behavior of Fe-Cr-C-Si-xNi (x = 1, 2 and 3 wt.%) alloys were investigated for 50 hours using a 20 kHz vibratory cavitation erosion test equipment. 1 wt.% Ni added Fe-based hardfacing alloy showed excellent cavitation erosion resistance, comparable to the stellite 6. Above 1 wt.% Ni, however, the erosion resistance deteriorated quickly. It is conjectured that Ni addition above 1 wt.%, which has been shown to increase the stacking fault energy (SFE), resulted in reduction of the work hardening rate during the erosion test. Therefore, the enhanced cavitation erosion resistance of the 1 wt.% Ni alloy over the 2 and 3 wt.% Ni alloys could be explained in terms of the SFE, Ms temperature and work hardening.

The repulsive bubble-bubble interaction in an ultrasonic field

2021 ◽  
Author(s):  
Ling-Ling Zhang ◽  
Wei-Zhong Chen ◽  
Yao-Rong Wu ◽  
Yang Shen ◽  
Guo-Ying Zhao
Keyword(s):  
Ultrasonic Field ◽  
Bubble Interaction

scholarly journals Comparison of cavitation erosion test results from venturi and vibratory facilities

Wear ◽  
1982 ◽  
Vol 76 (3) ◽  
pp. 269-292 ◽  
Author(s):  
Jiu-Gen He ◽  
F.G. Hammitt
Keyword(s):  
Cavitation Erosion ◽  
Test Results ◽  
Erosion Test

The Cavermod Device: Hydrodynamic Aspects and Erosion Tests

1999 ◽  
Vol 121 (2) ◽  
pp. 305-311 ◽  
Author(s):  
E. G. Filali ◽  
J. M. Michel
Keyword(s):  
Rotation Rate ◽  
Cavitation Erosion ◽  
Companion Paper ◽  
Core Collapse ◽  
Pure Aluminium ◽  
Force Measurements ◽  
Test Device ◽  
Erosion Model ◽  
Erosion Test

The Cavermod (CAVitation ERosion MODel) is an erosion test device first described by Dominguez-Cortazar et al. (1992, 1997). Recently, it was modified in two steps: first by increasing its maximum rotation rate (from 4500 to 8000 rpm) and second by shortening its vapor core (from 156 to 66 mm). This paper plans to present the main results which are obtained in both configurations (long and short vortex) and for “slow” or “rapid” regime of rotation. They mainly concern 1. the hydrodynamic aspects of the vapor core collapse, as deduced from observation of rapid films (evolution of the vortex length, collapse, velocity), 2. the erosion patterns produced on metallic targets such as pure aluminium and copper. A second companion paper will present the results of force measurements in both configuration and an attempt to estimate the local erosive pressures.

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