scholarly journals Mitigating cavitation erosion using biomimetic gas-entrapping microtextured surfaces (GEMS)

2020 ◽  
Vol 6 (13) ◽  
pp. eaax6192 ◽  
Author(s):  
Silvestre Roberto Gonzalez-Avila ◽  
Dang Minh Nguyen ◽  
Sankara Arunachalam ◽  
Eddy M. Domingues ◽  
Himanshu Mishra ◽  
...  

Cavitation refers to the formation and collapse of vapor bubbles near solid boundaries in high-speed flows, such as ship propellers and pumps. During this process, cavitation bubbles focus fluid energy on the solid surface by forming high-speed jets, leading to damage and downtime of machinery. In response, numerous surface treatments to counteract this effect have been explored, including perfluorinated coatings and surface hardening, but they all succumb to cavitation erosion eventually. Here, we report on biomimetic gas-entrapping microtextured surfaces (GEMS) that robustly entrap air when immersed in water regardless of the wetting nature of the substrate. Crucially, the entrapment of air inside the cavities repels cavitation bubbles away from the surface, thereby preventing cavitation damage. We provide mechanistic insights by treating the system as a potential flow problem of a multi-bubble system. Our findings present a possible avenue for mitigating cavitation erosion through the application of inexpensive and environmentally friendly materials.

2021 ◽  
Vol 1 (395) ◽  
pp. 13-34
Author(s):  
A. Pustoshny ◽  

Object and purpose of research. This paper discusses cavitation erosion on propeller blades. The purpose of this work is to review and analyse modern studies on cavitation erosion, as well as to apply these research results for better under-standing of cavitation damage risk on full-scale propellers. Materials and methods. The paper reviews recent studies on cavitation erosion, as well as the author’s own findings in cavitation erosion on full-scale steel propellers, analyzing the energy needed to create cavitation damage of recorded size. This energy was calculated as per the model based on the results of metallurgical studies discussing the effect of shot blasting upon steel properties. Comparison of these results with those obtained as per classic formulae for the collapse energy of cavita-tion bubble made it possible to estimate the conditions of cavitation erosion on propeller blades. Main results. The review of recent studies on cavitation erosion has shown that current progress in the technologies of experimental studies and computer-based simulations made it possible to considerably improve the knowledge about cavitation erosion process as compared to the level of the 20th century. This review shows that cavitation erosion studies followed three practically independent paths: experimental studies and computer-based simulation of flow around propeller blades with locali-zation of peaks for one or several criteria reflecting the intensity of cavitation energy fluctuations; the studies intended to esti-mate the pressure exerted by collapsing cavitation bubbles and emerging cumulative jets; and finally, the studies on the proper-ties of materials affected by cumulative jets and collapsing bubbles. At this point, it would be practicable to merge these three paths using the results of full-scale cavitation erosion analysis for propellers. KSRC findings in cavitation damage of full-scale steel propeller has shown that cavitation damage recorded in these studies might occur due to a certain combination between the required energy, bubble-blade interaction pressure and the size of affect-ed area on steel blade surface, and this combination, in its turn, might take place when cavitation bubbles consisting of vapour fraction with partial air content hit the blade surface and collapse. Conclusion. This paper shows the capabilities of modern research methods in obtaining new data on the inception mecha-nism of cavitation erosion. Still, to develop the methods for prediction of cavitation erosion (in particular, on propellers), it is necessary to merge the results obtained in different branches of cavitation studies. The basis for this merging could become a power-based analysis of cavitation processes, with help of the cavitation erosion model suggested in this paper and based on the similarity between cavitation erosion and shot-blasting.


2004 ◽  
Vol 261-263 ◽  
pp. 1397-1402
Author(s):  
Yun Hae Kim ◽  
Y.J. Son ◽  
B.H. Woo ◽  
C.W. Bae ◽  
S.M. Kim ◽  
...  

Cavitation-erosion is a hydrodynamic phenomenon that results in the formation and collapse of vapor bubbles in a liquid. Cavitation damage is encountered in a wide variety of fluid handling machinery and over a broad range of liquid pressures and temperatures. In this study, cavitation damage was investigated by using the piezoelectric vibrator with 20kHz, 50μm to cavity generation apparatus. At the first cavitation test, coated composite material specimens appear to generating the low bubbles due to damping vibration. This study is mainly compared with cavitation test (ASTM G 32) and modified cavitation test. And it is also concerned with phenomenon of cavitation-erosion on the several materials. In order to compare the both test methods, cavitaion weight loss and rate of the several materials in fresh-water and sea-water measured and observed with digital camera.


2012 ◽  
Vol 446-449 ◽  
pp. 2740-2744 ◽  
Author(s):  
Yi Min Xu ◽  
Hong Xuan Yang ◽  
Wei Zhao ◽  
Chun Ying Shen

Aeration facility is widely used to reduce cavitation erosion of discharge works caused by high speed flows and it has proved to be an economical, effective and successful measure. For a flow chute with complex boundary conditions, the air pressure and backwater in an aerator cavity are important factors that influence the flow aeration, and there are numerous and complex hydraulic factors to affect them. By the jet trajectory equation and a series of experimental tests, the air pressure and backwater in different aerator cavities are investigated. How these factors such as the size and style of aerator, the arc radius of the chute and flow discharge to influence the air pressure and backwater in an aerator cavity are revealed. These results can be referenced in designing aerators on the chute with a concave surface.


1988 ◽  
Author(s):  
K. KAILASANATH ◽  
J. GARDNER ◽  
E. ORAN ◽  
J. BORIS

1989 ◽  
Author(s):  
K. KAILASANATH ◽  
J. GARDNER ◽  
E. ORAN ◽  
J. BORIS

1996 ◽  
Author(s):  
P. Clancy ◽  
J.-H. Kim ◽  
M. Samimy

Author(s):  
V.V. VLASENKO ◽  
◽  
V.A. SABELNIKOV ◽  
S.S. MOLEV ◽  
O.V. VOLOSHCHENKO ◽  
...  

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