Surface functionalization by nanosecond-laser texturing for controlling hydrodynamic cavitation dynamics

Martin Petkovšek (Author), Matej Hočevar (Author), Peter Gregorčič (Author)

Abstract

The interaction between liquid flow and solid boundary can result in cavitation formation when the local pressure drops below vaporization threshold. The cavitation dynamics does not depend only on basic geometry, but also on surface roughness, chemistry and wettability. From application point of view, controlling cavitation in fluid flows by surface functionalization is of great importance to avoid the unwanted effects of hydrodynamic cavitation (erosion, noise and vibrations). However, it could be also used for intensification of various physical and chemical processes. In this work, the surfaces of 10-mm stainless steel cylinders are laser textured in order to demonstrate how hydrodynamic cavitation behavior can be controlled by surface modification. The surface properties are modified by using a nanosecond (10-28 ns) fiber laser (wavelength of 1060 nm). In such a way, surfaces with different topographies and wettability were produced and tested in a cavitation tunnel at different cavitation numbers (1.0-2.6). Cavitation characteristics behind functionalized cylindrical surfaces were monitored simultaneously by high-speed visualization (20,000 fps) and high frequency pressure transducers. The results clearly show that cavitation characteristics differ significantly between different micro-structured surfaces. On some surfaces incipient cavitation is delayed and cavitation extent decreased in comparison with the reference - a highly polished cylinder. It is also shown that the increased surface wettability (i.e., hydrophilicity) delays the incipient cavitation.

Keywords

hydrodynamic cavitation;laser surface engineering;fluid dynamics;laser texturing;

Data

Language:	English
Year of publishing:	2020
Typology:	1.01 - Original Scientific Article
Organization:	UL FS - Faculty of Mechanical Engineering
UDC:	532.5(045)
COBISS:	17154075
ISSN:	1350-4177
Views:	792
Downloads:	576
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	hidrodinamska kavitacija;laserski inženiring površin;dinamika fluidov;laserske obdelave;
Type (COBISS):	Article
Pages:	str. 1-10
Issue:	ǂVol. ǂ67
Chronology:	2020
DOI:	10.1016/j.ultsonch.2020.105126
ID:	11752593